{"product_id":"hanna-hi93720-calcium-hardness-lr-reagents","title":"Hanna HI93720 Calcium Hardness LR Reagents, 100\/300 Tests","description":"\u003cdiv id=\"bts-hi93720-description\" style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;max-width:1400px;margin:0 auto;padding:20px 12px;color:#26332C;background:#fff;\"\u003e\n\u003cdiv style=\"display:flex;flex-wrap:wrap;align-items:center;gap:20px;padding-bottom:20px;margin-bottom:24px;border-bottom:1px solid #e0e0e0;\"\u003e\n\u003cdiv style=\"flex:1 1 360px;min-width:0;box-sizing:border-box;\"\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eHANNA PHOTOMETER REAGENTS · HI93720\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eResolve low-level calcium hardness, not dissolved calcium.\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eKeep the HI97720 calcium-hardness method supplied with the matched three-liquid reagent set. Choose 100 or 300 determinations for low-hardness water monitoring without changing the chemistry or reporting basis.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cfigure style=\"flex:0 1 310px;min-width:0;margin:0;text-align:center;box-sizing:border-box;\"\u003e\n\u003cimg alt=\"Official Hanna HI93720 reagent set reference photo\" height=\"1200\" loading=\"lazy\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/calcium-hardness-reagents-100-tests-hi93720-01__64202.1575313059.jpg?v=1793630455\" style=\"width:100%;max-width:300px;height:auto;object-fit:contain;\" width=\"1200\"\u003e\n\u003cfigcaption style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-size:0.9rem;margin-top:8px;\"\u003eOfficial Hanna calcium-hardness reagent-set reference photo. Printed lot and expiry markings are illustrative, not supplied-stock dates.\u003c\/figcaption\u003e\u003c\/figure\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"background:#F1F7F3;border-left:3px solid #245B45;padding:20px;box-sizing:border-box;margin:0 0 24px;\"\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eMatch the method, not just the element name\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eHI97720: 0.00 to 2.70 mg\/L as CaCO₃. Calmagite chemistry measures calcium hardness as calcium carbonate over 0.00 to 2.70 mg\/L as CaCO₃ on the HI97720. This is not direct dissolved calcium as Ca²⁺, not HI937521 oxalate reagents, and not an undiluted swimming-pool hardness range.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eWhat the selected pack supplies\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eA complete calcium-hardness A\/B\/C liquid reagent set for the selected 100 or 300 tests. This is reagent replenishment, not a photometer or CAL Check kit.\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eWhere this method fits\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eThe HI97720 is intended for low hardness levels such as those found in water-purification systems. For a documented 100-fold dilution, add 0.5 mL of sample to a clean, dry 50 mL beaker and bring to the 50 mL mark with hardness-free water. Account for dilution when interpreting the original sample; do not treat the native range as a pool-water range.\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eThe HI97720 workflow at a glance\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eRinse a graduated beaker with unreacted sample and fill it to 50 mL. Add 0.5 mL of reagent A, swirl, then add 0.5 mL of reagent B and swirl. Fill two cuvettes with 10 mL of this treated sample. Add one drop of reagent C to the first cuvette only, stopper, cap and invert to mix: this is the blank. Align its cap notch with the holder groove and zero the HI97720. Replace it with the second cuvette, aligned in the same way, and press Read for calcium hardness as CaCO₃.\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eCheck the sample matrix\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eExcessive heavy metals can interfere. Calcium contamination in the beaker, syringes or cuvettes affects this low-level test; repeat cleanliness checks until results are consistent. Dilutions require hardness-free water, not ordinary tap water.\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eChoose a pack around your workload\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eHI93720-01 supplies 100 tests; HI93720-03 supplies 300 tests. The larger pack supplies three times the determinations, not a different measuring range. One order quantity means one complete selected pack. Choose by testing frequency and the lot\/expiry markings on supplied stock.\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eWhat to have beside the reagent set\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eSupply the compatible photometer, cuvettes with stoppers and caps, and the measuring\/dispensing accessories required by the method separately. Use hardness-free water for calcium-hardness dilution. CAL Check standards are separate instrument-verification materials, not replacements for sample reagents.\u003c\/p\u003e\n\u003ch4 style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;font-weight:400;line-height:1.35;margin:0 0 16px;color:#245B45;\"\u003eHandling before you begin\u003c\/h4\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eReview all three US component SDS. Reagent B may corrode metals and causes severe skin burns and eye damage; use the specified protection and handling controls. Hanna flags both complete pack sizes as Dangerous Goods for ground shipment only.\u003c\/p\u003e\n\u003cp style=\"font-family:'Open Sans',sans-serif;font-weight:300;font-size:1rem;line-height:1.65;box-sizing:border-box;margin:0 0 16px;\"\u003eUse the linked HI97720 instrument manual as the method reference for the complete procedure, precautions and instrument operation. This is not a separate reagent instruction manual.\u003c\/p\u003e\n\u003cdiv class=\"faq_block\" style=\"border-top:1px solid #e0e0e0;margin-top:24px;\"\u003e\u003cdiv itemscope=\"\" itemtype=\"https:\/\/schema.org\/FAQPage\" style=\"width: 100%; padding: 20px 0; font-family: 'Open Sans', sans-serif; font-weight: 300; color: #333;line-height:1.15;\"\u003e\n\u003ch3 style=\"font-size:1.1rem;font-weight:400;margin:0 0 16px;color:#245B45;\"\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eShould I choose 100 or 300 tests?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eHI93720-01 supplies 100 tests; HI93720-03 supplies 300 tests. Both are complete reagent sets for the same method. Choose by expected workload and marked expiry dates, not by a different analytical range.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eIs this calcium hardness or dissolved calcium?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eIt is calcium hardness, reported as mg\/L CaCO₃. HI97720 uses calmagite chemistry over 0.00 to 2.70 mg\/L as CaCO₃. HI937521 measures calcium directly with different chemistry and is not a substitute.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eWhy does the method need two cuvettes?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eBoth receive 10 mL of the sample treated with A and B. Add one drop of C to only the first cuvette and use that as the blank. Zero with the blank, then read the second cuvette. Do not add C to both.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eCan I measure pool water without dilution?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eDo not assume that. The native HI97720 range is low-level hardness. The manual documents a 100-fold dilution using 0.5 mL sample brought to 50 mL with hardness-free water; follow it and account for dilution when interpreting results.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eWhy is clean glassware especially important?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eThis low-range method detects calcium contamination from the beaker, syringes and sample cells. Repeat the cleanliness test until results are consistent and use hardness-free water for dilution.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eWhich photometers are documented for HI93720?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eBoth packs are documented for HI97720. The procedure and range on this page use HI97720 as the primary reference; follow the exact instrument method when using another model.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eWhich sample conditions should I check first?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eExcessive heavy metals can interfere. Calcium contamination in the beaker, syringes or cuvettes affects this low-level test; repeat cleanliness checks until results are consistent. Dilutions require hardness-free water, not ordinary tap water.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\u003cdetails itemprop=\"mainEntity\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Question\" style=\"border: 1px solid #e0e0e0; border-radius: 8px; margin: 0 0 10px 0; background: #fff;\"\u003e\u003csummary itemprop=\"name\" style=\"cursor: pointer; padding: 14px 16px; font-size: 1rem; font-weight: 400; list-style-position: inside;\"\u003eAre the instrument, cuvettes and CAL Check standards included?\u003c\/summary\u003e\u003cdiv itemprop=\"acceptedAnswer\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Answer\" style=\"padding: 0 16px 14px 16px;\"\u003e\u003cp itemprop=\"text\" style=\"font-size: 0.97rem; line-height: 1.6; margin: 0;\"\u003eNo. These are reagent-only packs. Provide the photometer, cuvettes with stoppers and caps, and the method-required sampling and dispensing accessories separately. CAL Check standards are separate instrument-validation materials, not test reagents.\u003c\/p\u003e\u003c\/div\u003e\u003c\/details\u003e\n\u003c\/div\u003e\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Hanna Instruments","offers":[{"title":"100 tests | HI93720-01","offer_id":53426726175018,"sku":"BTS-HI93720-01","price":74.79,"currency_code":"USD","in_stock":true},{"title":"300 tests | HI93720-03","offer_id":53426726207786,"sku":"BTS-HI93720-03","price":214.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0896\/1579\/4474\/files\/calcium-hardness-reagents-100-tests-hi93720-01__64202.1575313059.jpg?v=1793630455","url":"https:\/\/bluetigerscientific.com\/products\/hanna-hi93720-calcium-hardness-lr-reagents","provider":"Blue Tiger Scientific","version":"1.0","type":"link"}