{"product_id":"apera-sx725-portable-ph-dissolved-oxygen-meter-kit","title":"Apera SX725 Portable pH and Dissolved Oxygen Meter Kit with DO500 Polarographic Probe","description":"\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:1400px;margin:0 auto;color:#26332C;font-size:1rem;line-height:1.75;\" id=\"bts-sx725-description\"\u003e\n\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(20px,4vw,48px);border:1px solid #B7D0BF;background:#F1F7F3;border-radius:14px;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:clamp(24px,4vw,48px);\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;font-weight:600;letter-spacing:.12em;text-transform:uppercase;color:#245B45;margin:0 0 12px;\"\u003eAPERA INSTRUMENTS \/ SX725 \/ AI465\u003c\/p\u003e\n\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eTwo water checks.\u003cbr\u003eOne probe connection at a time.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eSX725 pairs a DO500 polarographic oxygen probe with a 201T-S pH\/temperature electrode for sequential testing of general water solutions. Change electrodes to change measurement tasks. Its backlit screen, 300-set memory and fitted carrying case support a practical field workflow.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eChoose AI465 when you need pH and DO in one case, not simultaneous multi-channel monitoring. The 8-pin input recognizes the connected electrode; temperature accompanies the selected measurement. The included probes are for general aqueous samples, not every liquid the meter can display a number for.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;margin:0;min-width:0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"SX725 meter connected to its DO500 probe\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:340px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eSX725 shown in its DO configuration. Disconnect this electrode before connecting the 201T-S for pH; this is not concurrent pH\/DO measurement.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003cdetails id=\"bts-sx700-kit-guide\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;border:1px solid #FF931A;border-radius:10px;margin:24px 0;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;justify-content:space-between;gap:16px;padding:20px;background:#FF931A;color:#172b4d;border-radius:10px;cursor:pointer;line-height:1.5;\"\u003e\u003cspan style=\"flex:1;min-width:0;\"\u003e\u003cspan style=\"display:block;font-size:clamp(17px,2.6vw,21px);font-weight:700;\"\u003eWhich meter kit fits my measurement?\u003c\/span\u003e\u003cspan class=\"bts-sp-when-closed\" style=\"display:block;font-size:.88rem;margin-top:5px;\"\u003eClick or tap to compare all eight measurement configurations\u003c\/span\u003e\u003cspan class=\"bts-sp-when-open\" style=\"font-size:.88rem;\"\u003eClick or tap here to close the guide\u003c\/span\u003e\u003c\/span\u003e\u003cspan class=\"bts-sp-toggle\" aria-hidden=\"true\" style=\"flex:0 0 38px;width:38px;height:38px;display:flex;align-items:center;justify-content:center;border-radius:50%;background:white;font-size:27px;\"\u003e\u003c\/span\u003e\u003c\/summary\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:20px;\"\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eEach card opens that model page. Match the supplied electrode and documented sample method. pH, ORP, conductivity and polarographic dissolved oxygen are different measurements. Match the parameter and meter format before comparing accessories; optional items are not supplied unless the exact kit list says so.\u003c\/p\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;gap:14px;\"\u003e\n\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX711\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx711-portable-ph-mv-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx711-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX711\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX711\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI460\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH and temperature\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003e201T-S pH\/temperature probe; ORP electrode separate.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX711 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX721\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx721-portable-ph-orp-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx721-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX721\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX721\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI463\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH and ORP kit\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eSeparate pH and ORP probes; one connection at a time.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX721 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX723\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx723-portable-ph-conductivity-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx723-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX723\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX723\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI477\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH and conductivity kit\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eSeparate 201T-S and 2301T-S probes; sequential tests.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX723 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX716\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx716-portable-polarographic-dissolved-oxygen-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX716\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX716\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI461\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003ePolarographic dissolved oxygen\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eDO500 membrane probe; polarization and movement required.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX716 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX725\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx725-portable-ph-dissolved-oxygen-meter-kit\" aria-current=\"page\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:2px solid #FF931A;background:#FFF9F0;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX725\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX725\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI465\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH and dissolved oxygen\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eSwap the pH and DO500 probes for sequential tests.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eCurrent item\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX731\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx731-portable-ph-orp-conductivity-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx731-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX731\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX731\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI467\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH, ORP and conductivity\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eThree supplied sensor types; not simultaneous acquisition.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX731 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX736\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx736-portable-ph-conductivity-dissolved-oxygen-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx736-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX736\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX736\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI468\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH, conductivity and DO\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eThree probe workflows with distinct storage and calibration.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX736 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\u003ca class=\"bts-sx700-kit-link\" data-sx700-kit=\"SX751\" href=\"https:\/\/bluetigerscientific.com\/products\/apera-sx751-portable-ph-orp-conductivity-dissolved-oxygen-meter-kit\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;align-items:flex-start;gap:14px;flex:1 1 300px;min-width:0;padding:18px;border:1px solid #e0e0e0;background:white;border-radius:9px;text-decoration:none;color:#26332C;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx751-hero-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=200\" alt=\"Apera SX751\" width=\"72\" height=\"72\" loading=\"lazy\" style=\"width:72px;height:72px;flex:0 0 72px;object-fit:contain;background:white;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1;min-width:0;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:700;line-height:1.3;margin:0 0 4px;color:#245B45;\"\u003eSX751\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.76rem;margin:0 0 9px;\"\u003eAI469\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.95rem;font-weight:600;line-height:1.5;margin:0 0 6px;\"\u003epH, ORP, conductivity and DO\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;margin:0 0 12px;\"\u003eFour probe workflows; one input and model-specific records.\u003c\/p\u003e\n\u003cspan style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:inline-block;padding:6px 9px;border-radius:5px;background:#FFF0DD;font-size:.85rem;font-weight:700;\"\u003eView SX751 →\u003c\/span\u003e\n\u003c\/div\u003e\u003c\/a\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/details\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eChoose the electrode for the sample.\u003c\/h2\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;gap:16px;\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 240px;min-width:0;padding:24px;background:#fff;border:1px solid #DCE6DF;border-radius:10px;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.07rem;font-weight:600;color:#245B45;margin:0 0 12px;\"\u003eCompensate for the water you are testing\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eDO500 contains temperature and salinity sensors. DO compensation is automatic over 0 to 45°C and 0 to 45 ppt; barometric pressure is entered manually over 66 to 200 kPa. The P3 example of 101.3 means kPa, not mbar. These corrections do not remove the need for calibration, clean sensors or adequate water movement.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 240px;min-width:0;padding:24px;background:#fff;border:1px solid #DCE6DF;border-radius:10px;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.07rem;font-weight:600;color:#245B45;margin:0 0 12px;\"\u003eRecognize the electrode, then select the task\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eConnect the 201T-S for pH and temperature or the DO500 for dissolved oxygen and temperature. Automatic electrode recognition is not simultaneous pH\/DO acquisition. The manual also specifies an mV mode, but an ORP electrode and any required connection accessory are not included.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 240px;min-width:0;padding:24px;background:#fff;border:1px solid #DCE6DF;border-radius:10px;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.07rem;font-weight:600;color:#245B45;margin:0 0 12px;\"\u003eReplace the membrane, not the whole workflow\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eThe DO503 cap holds a sensitive membrane over the gold cathode and silver anode. DO502 inner solution completes the serviceable assembly. Keep spare caps clean and avoid touching their membrane faces. The kit includes the maintenance materials and a screwdriver; replacement frequency depends on condition, not a promised fixed service interval.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:clamp(24px,4vw,48px);\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\n\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eKnow what this configuration supplies.\u003c\/h2\u003e\n\u003cdiv aria-label=\"Included item table\" role=\"region\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;overflow-x:auto;width:100%;max-width:100%;\" tabindex=\"0\"\u003e\u003ctable style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;border-collapse:collapse;font-size:1rem;border:1px solid #e0e0e0;table-layout:fixed;\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth scope=\"col\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;background:#f5f5f5;text-align:left;padding:12px;font-size:1rem;font-weight:700;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eIncluded item\u003c\/th\u003e\n\u003cth scope=\"col\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;background:#f5f5f5;text-align:left;padding:12px;font-size:1rem;font-weight:700;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eOrder contents\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eSX725 meter\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eOne handheld instrument.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eDO500 polarographic DO electrode\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eOne 8-pin probe with temperature\/salinity sensors and calibration\/storage sleeve.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003e201T-S pH\/temperature electrode\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eOne 8-pin combination electrode with KCl storage bottle.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003epH calibration buffers\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003epH 4.00, 7.00 and 10.01; one 50 mL bottle each.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eDO502 inner solution\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eOne 30 mL bottle of DO electrolyte.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eDO503 membrane caps\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eThree spare caps.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eDO504 polishing paper\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eTwo pieces for the gold cathode.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f9f9f9;\"\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:32%;font-weight:600;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eService and transport items\u003c\/td\u003e\n\u003ctd style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:12px;font-size:1rem;line-height:1.6;vertical-align:top;border:1px solid #e0e0e0;width:50%;overflow-wrap:anywhere;min-width:0;\"\u003eOne screwdriver, two spare AA batteries, operation manual and carrying case.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;margin:0;min-width:0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-kit-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-kit-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-kit-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-kit-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Numbered SX725 carrying-case contents\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:500px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eKit legend: 1 SX725; 2 201T-S; 3 DO500; 4 pH 7.00 buffer; 5 pH 10.01 buffer; 6 pH 4.00 buffer; 7 three spare DO503 caps; 8 two polishing-paper pieces; 9 DO502, 30 mL; 10 two AA batteries; 11 screwdriver; 12 manual. Each buffer is 50 mL.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;margin:0;min-width:0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-open-case-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-open-case-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-open-case-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-open-case-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Open SX725 case with both electrodes and accessories\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:700px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eSeparate compartments hold the two electrodes, three pH buffers, electrolyte, spare caps and service tools.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eMatch the sample and preparation method.\u003c\/h2\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;gap:16px;\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 240px;min-width:0;padding:24px;background:#fff;border:1px solid #DCE6DF;border-radius:10px;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.07rem;font-weight:600;color:#245B45;margin:0 0 12px;\"\u003eAquaculture and surface-water rounds\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eCompare oxygen conditions in compatible pond, aquarium or surface-water samples. Let the probe approach sample temperature and maintain flow across the membrane. Record location and collection time separately so readings remain meaningful after on-meter recall.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 240px;min-width:0;padding:24px;background:#fff;border:1px solid #DCE6DF;border-radius:10px;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.07rem;font-weight:600;color:#245B45;margin:0 0 12px;\"\u003eWater-treatment pH and oxygen checks\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eUse the two electrodes in separate measurement steps. Rinse between solutions and calibrate each method independently. Conductivity, TDS and resistivity are not included measurement channels; the DO salinity sensor provides oxygen compensation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 240px;min-width:0;padding:24px;background:#fff;border:1px solid #DCE6DF;border-radius:10px;\"\u003e\n\u003ch3 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.07rem;font-weight:600;color:#245B45;margin:0 0 12px;\"\u003eTraining with visible maintenance steps\u003c\/h3\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eThe replaceable membrane, sleeve and original electrode figures make preparation and care easy to explain. A field reading does not establish potability, regulatory compliance or biological safety. Strong acidic or alkaline water and organic solutions are outside DO500’s listed suitable samples.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:clamp(24px,4vw,48px);\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"calibration-panel\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-calibration-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-calibration-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-calibration-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-calibration-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Original SX725 saturated-oxygen calibration illustration\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:500px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eUse the moist-sponge sleeve for routine 100% calibration. After polarization, allow three to five minutes or longer until stable before confirming. The pictured reading is an illustration, not the target value to enter manually.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\n\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003ePolarize first.\u003cbr\u003eCalibrate, then keep the water moving.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eConnect DO500 to the powered meter and allow five minutes of polarization after every power-on. After changing the membrane cap or electrolyte, allow 30 minutes instead. The response specification is no more than 30 seconds to 90% response at 25°C, not a guarantee of a fully stable result in 30 seconds.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eFor routine 100% calibration, moisten the sleeve sponge with several drops of distilled water without making it drip. Insert the probe, tighten the sleeve cap and enter CAL. Allow three to five minutes, longer if unstable, then confirm only after stabilization. Keep calibration and sample temperatures within 10°C; for a larger difference, precondition the probe in sample water for about ten minutes.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eImmerse above the temperature sensor and hold the probe at 45° to 75° to the water surface. In flowing water, wait for stability and swirl slowly if needed. In static water, keep swirling faster than 5 cm\/s for one to five minutes and continue while recording. A large temperature difference requires more than three minutes. Stopping motion lets the electrode deplete nearby oxygen.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eThe specification also lists air-saturated water, but the detailed routine procedure uses water-saturated air in the sleeve. Optional zero calibration is intended for demanding work below 1.0 ppm. Follow the manual’s fresh sodium-sulfite solution, 15-minute polarization and acceptance checks. Arbitrary custom DO calibration points are not documented. Salinity is factory-calibrated; after electrode replacement, the P2 procedure uses separately purchased 12.88 mS\/cm standard.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eFor pH, rinse the 201T-S, briefly stir in buffer, then hold still until stable. Use one, two or three points from the selected USA, NIST or China series; the kit supplies pH 4.00, 7.00 and 10.01. Calibrate a new pH electrode at all three points. Do not apply the DO requirement for continuous swirling to a pH reading.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"compensation-panel\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-compensation-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-compensation-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-compensation-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-compensation-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Original temperature, salinity and pressure display examples\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:620px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eTemperature and salinity compensation are automatic; P3 barometric pressure is entered manually. The illustrated 101.3 is kPa, equal to 1013 mbar, not 101.3 mbar. The artwork does not guarantee accuracy under unsuitable sample conditions.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eUnderstand the sensing end and connections.\u003c\/h2\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:24px;\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 300px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;margin:0;min-width:0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-ph-configuration-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-ph-configuration-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-ph-configuration-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-ph-configuration-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"SX725 connected to the 201T-S pH electrode\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:480px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eThe 201T-S supplies pH and temperature through one 8-pin connection. Its KCl storage bottle is removed before testing.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 300px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"parameter-panel\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-parameter-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-parameter-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-parameter-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-parameter-panel-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Manufacturer panel showing separate SX725 pH and DO configurations\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:480px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eLeft: 201T-S for pH and temperature. Right: DO500 for oxygen and temperature. These are alternative connections, not simultaneous channels.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 300px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"do500-anatomy\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-do500-anatomy-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-do500-anatomy-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-do500-anatomy-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-do500-anatomy-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Labeled DO500 temperature and salinity sensors, anode, cathode and membrane cap\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:480px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eOriginal DO500 anatomy: temperature and salinity sensors sit above the replaceable membrane cap; the silver anode and gold cathode are inside. This is an oxygen-consuming polarographic system, not an optical sensing cap.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:clamp(24px,4vw,48px);\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\n\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eKeep the membrane clean.\u003cbr\u003eKeep the sleeve sponge moist.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eBetween uses, protect DO500 in its calibration\/storage sleeve with the sponge moist from a few drops of distilled water, not dripping. Do not fill this sleeve with pH KCl storage solution. Rinse the probe after testing and inspect the membrane and electrolyte for damage or bubbles. Keep the electrical connector clean and dry.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eReplace a wrinkled, cracked or damaged membrane, or investigate slow response and obvious errors. Unscrew the cap, rinse the exposed electrode with distilled water and shake off excess. Wipe the gold cathode with clean tissue. Slowly add fresh DO502 to a new DO503 cap without bubbles, stand it on a table and screw the electrode vertically into it. Wipe expelled electrolyte, rinse and check again for bubbles; reassemble if necessary.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eFor a contaminated gold cathode, use DO504 polishing paper lightly along the curved gold surface, then clean, rinse and refill as instructed. Never brush the platinum-black salinity sensor; swirl it in pure water instead. Re-polarize after fresh electrolyte and recalibrate before measurement. Handle electrolyte with appropriate protection and consult its safety instructions.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eThe 201T-S needs different storage: keep its glass bulb in the supplied KCl storage bottle, never in pure water. Its gel reference electrolyte is not refillable. Rinse before and after pH use; never rub the glass membrane. Do not transfer DO500 electrolyte or cathode-polishing instructions to the pH electrode.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eThe current 201T-S listing excludes low-ion water, strong-base samples above pH 12 and highly corrosive liquids. Its probe guide also cautions against frequent testing below pH 2 or above pH 12 and prolonged exposure above 50°C; 0 to 60°C is not a continuous-use guarantee.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;margin:0;min-width:0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-membrane-caps-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-membrane-caps-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-membrane-caps-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-membrane-caps-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Three replacement DO503 membrane caps\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:500px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eThree spare DO503 caps are supplied. Avoid touching the membrane faces; replace damaged, wrinkled or cracked membranes and investigate slow response.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"electrolyte\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-electrolyte-20261016-sx700-eight.webp?v=1792171717\u0026amp;width=1000\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-electrolyte-20261016-sx700-eight.webp?v=1792171717\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-electrolyte-20261016-sx700-eight.webp?v=1792171717\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx716-electrolyte-20261016-sx700-eight.webp?v=1792171717\u0026amp;width=1000 1000w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"DO502 inner-solution refill bottle\" width=\"1200\" height=\"1200\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:500px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eDO502 is the 30 mL electrolyte refill for the membrane assembly, not a calibration standard or pH storage liquid. Fill slowly without bubbles and re-polarize after refilling.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"probe-sleeve-figure\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-probe-sleeve-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=570\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-probe-sleeve-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-probe-sleeve-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=570 570w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Original numbered DO500 sleeve and electrode diagram\" width=\"570\" height=\"494\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:500px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eOriginal diagram legend: 1 DO500; 2 sleeve cap; 3 sleeve; 4 water-moistened sponge; 5 bottom lid; 6 temperature sensor; 7 membrane cap; 8 gold cathode; 9 silver anode; 10 salinity sensor. Keep the sponge moist, not dripping.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:clamp(24px,4vw,48px);\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:24px;\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 300px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"lcd-legend\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-lcd-legend-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=442\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-lcd-legend-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-lcd-legend-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=442 442w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Original manual display diagram with numbered indicators\" width=\"442\" height=\"360\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:420px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eDisplay legend: 1 parameter; 2 result; 3 record number and M+\/RM; 4 unit; 5 temperature; 6 stability smile; 7 calibration status; 8 low battery. The all-segment diagram explains the screen and is not a sample reading.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 300px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"connector-figure\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-connector-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=900\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-connector-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=360 360w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-connector-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=640 640w, https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-connector-figure-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=900 900w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"Original electrode connection and locking-ring illustration\" width=\"900\" height=\"600\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:420px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eAlign the notches and push straight in while holding the metal ring, then tighten the ring. To remove, loosen the ring and pull straight out. Never twist the black rubber part. One electrode connects at a time.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\n\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eRead the display. Check the measurement mode.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eUse the physical controls for measurement, calibration and the documented record functions. Check units, temperature, calibration indicators and the selected parameter before assigning a result to a sample. Screen values in photographs are illustrative, not sample results. The model-specific record and output workflow is explained below.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eFollow the exact parameter-specific calibration procedure, using the required standard, solution or calibration atmosphere. Temperature compensation does not make different sample temperatures, preparation methods or chemistry equivalent. Follow the model-specific meter and electrode instructions before extending the method to a new sample.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;display:flex;flex-wrap:wrap;align-items:center;gap:clamp(24px,4vw,48px);\"\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\n\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eSave 300 sets.\u003cbr\u003eRecall locally and keep a separate field log.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eWhen the smile remains on screen, a short press of M+\/RM stores the reading. SX725 holds up to 300 sets containing serial number, measurement value, unit and temperature. The manual states 300 sets for the meter, not 300 per mode; it does not specify a per-mode allocation.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eA long press recalls the last saved record; use the review keys to browse. The manual’s delete operation in recall mode clears all saved data, so transcribe needed readings first. No date\/time fields, real-time clock setting, timed automatic logging, USB, Bluetooth or PC-Link export workflow is documented for this model. “Data logging” here means operator-initiated save and recall.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;flex:1 1 340px;min-width:0;\"\u003e\u003cfigure style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;width:100%;max-width:620px;margin:0 auto;min-width:0;\" data-mfr-feature=\"memory-indicators\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-memory-indicators-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=156\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-memory-indicators-20261016-sx700-eight.webp?v=1792171716\u0026amp;width=156 156w\" sizes=\"(max-width:600px) calc(100vw - 80px), 560px\" alt=\"M plus and RM record indicators from the original LCD diagram\" width=\"156\" height=\"66\" loading=\"lazy\" decoding=\"async\" style=\"display:block;width:100%;max-width:156px;height:auto;object-fit:contain;box-sizing:border-box;margin:0 auto;\"\u003e\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.86rem;line-height:1.65;color:#5D6C63;margin-top:12px;\"\u003eM+ accompanies a manually saved reading; RM identifies a recalled reading. Record numbers are not timestamps. 300 sets are available on this model; no timed logging or computer export is documented.\u003c\/figcaption\u003e\u003c\/figure\u003e\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:clamp(28px,5vw,56px) 0;border-bottom:1px solid #B7D0BF;\"\u003e\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eCompare another measurement format.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eRelated workflow: \u003ca href=\"https:\/\/bluetigerscientific.com\/products\/apera-do850-10-ft-optical-dissolved-oxygen-meter-kit\" style=\"color:#245B45;text-decoration:underline;font-weight:600;\"\u003eApera DO850 Portable Optical Dissolved Oxygen Meter Kit, 10-ft Cable | AI480\u003c\/a\u003e. The linked optical DO kit has a different sensor technology and maintenance workflow; its probe or cap is not interchangeable with DO500. It is a DO-workflow option, not a replacement for this kit’s other parameters. Compare the exact supplied sensors, measurement parameter, accessories and data features rather than assuming similar model names mean identical kits.\u003c\/p\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:28px 0;line-height:1.15;\" id=\"bts-sx725-faq\"\u003e\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1.1rem;font-weight:600;margin:0 0 16px;\"\u003eSX725 buyer questions\u003c\/h2\u003e\n\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eIs this an optical dissolved oxygen meter?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eNo. The included DO500 uses a polarographic membrane system with electrolyte, a gold cathode and silver anode. It consumes oxygen and requires polarization and water movement. DO803 optical-probe claims, no-flow claims and optical-cap warranty terms do not apply.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eHow long does a DO measurement take?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eAllow five minutes after power-on, or 30 minutes after fresh electrolyte or a new cap. The ≤30-second specification is 90% response at 25°C. The manual’s field procedure typically takes one to five minutes and requires actual stability, temperature equilibration and continuous movement in still water.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eWhat calibration solutions are included?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eDO502 is 30 mL of electrode electrolyte, not a DO calibration standard. Routine oxygen calibration uses the moist sleeve. Sodium sulfite for optional zero calibration and 12.88 mS\/cm salinity standard are not listed in the kit. SX725 also includes 50 mL each of pH 4.00, 7.00 and 10.01 buffer.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eCan pH and DO be measured at the same time?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eNo concurrent pH\/DO workflow is documented. Connect one 8-pin electrode at a time; recognition selects the appropriate parameter. Temperature is read with that electrode. ORP requires a separately purchased suitable electrode; no ORP probe is in AI465.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eWhich temperature limits matter?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eThe meter’s operating environment is 5 to 35°C at ≤85% humidity. DO compensation covers 0 to 45°C, while the current DO500 listing gives a 0 to 50°C probe range. These are different limits. The current 201T-S listing specifies 0 to 13 pH and 0 to 60°C; its PDF lists wider ranges. Use the narrower current probe limits and avoid prolonged high-temperature work. The current 201T-S listing excludes low-ion water, strong-base samples above pH 12 and highly corrosive liquids. Its probe guide also cautions against frequent testing below pH 2 or above pH 12 and prolonged exposure above 50°C; 0 to 60°C is not a continuous-use guarantee.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eAre the caps, electrolyte and service tools supplied?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eYes: three spare DO503 membrane caps, one 30 mL DO502 refill, two pieces of DO504 cathode-polishing paper, a screwdriver, two spare AA batteries, manual and case accompany the meter and DO500. The probe includes its calibration\/storage sleeve. AI465 adds a 201T-S electrode and three 50 mL pH buffers.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eCan I export records or automatically log a time series?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eThe exact manual documents 300 manually saved sets with on-meter recall. It does not document timestamps, a logging interval, USB, Bluetooth or computer export. Preserve time, sample identity and readings in your own field record. Do not assume separate 300-record banks for different units or modes.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails style=\"border:1px solid #e0e0e0;border-radius:8px;margin-bottom:10px;background:white;\"\u003e\u003csummary style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:14px 16px;cursor:pointer;font-weight:600;font-size:1rem;line-height:1.15;\"\u003eWhat warranty applies to the meter, probes and consumables?\u003c\/summary\u003e\u003cdiv style=\"padding:0 16px 14px;\"\u003e\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:.97rem;line-height:1.6;margin:0;\"\u003eThe current US SX725 listing and v3.0 meter manual state three years for the instrument and six months for the probes from delivery, for covered material or workmanship defects, with repair or replacement at Apera’s option. They exclude normal wear, accidental damage, improper use or storage, transportation damage, neglected instructions or maintenance, unauthorized repair or modifications and external causes. No separate fixed warranty duration is published for DO503 membrane caps or DO502 refill in the reviewed product pages; do not assume optical-cap coverage or free routine consumable replacement.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003c\/section\u003e\u003csection style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;padding:28px;background:#F1F7F3;border:1px solid #B7D0BF;border-radius:12px;\"\u003e\u003ch2 style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:clamp(24px,4vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.02em;color:#245B45;margin:0 0 20px;\"\u003eConfirm the exact configuration before ordering.\u003c\/h2\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;box-sizing:border-box;font-size:1rem;line-height:1.75;margin:0 0 16px;\"\u003eReview SX725 AI465 against the sample, supplied electrode and documented method. Return to the live price and ordering controls when the configuration fits your work.\u003c\/p\u003e\n\u003ca href=\"#\" style=\"color:#245B45;text-decoration:underline;font-weight:600;\"\u003eBack to price and ordering ↑\u003c\/a\u003e\u003c\/section\u003e\n\u003c\/div\u003e","brand":"Apera Instruments","offers":[{"title":"Default Title","offer_id":52969306816810,"sku":"BTS-AI465","price":595.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/apera-sx725-hero-20261016-sx700-eight.webp?v=1792171716","url":"https:\/\/bluetigerscientific.com\/products\/apera-sx725-portable-ph-dissolved-oxygen-meter-kit","provider":"Blue Tiger Scientific","version":"1.0","type":"link"}