APERA INSTRUMENTS / PH850-SL / AI5537

Prepared soil.
Direct pH, carefully measured.

PH850-SL pairs the portable PH850 Value-series meter with the LabSen 553 pH/temperature spear electrode for direct measurements in prepared, moist soil and for soil slurry testing. The specialized probe changes the sampling method, not the need for careful preparation.

Choose this kit for repeatable soil pH checks with a separate written sample log. The PVC-bodied electrode has a non-refillable polymer reference, ceramic and open junctions, and an integrated temperature sensor. Its glass spear is a sensor, not a digging rod.

A spear designed for soil contact

The conical glass sensing end and ceramic/open junction arrangement are designed for soil and soil slurry. The polymer electrolyte avoids routine reference refilling, while the Long-Life reference supports stable operation. These features do not make the glass unbreakable. Prepare an opening with a separate tool, avoid excessive force and never push the electrode into dry or compacted ground.

Portable readings, straightforward controls

The PH850 Value-series meter shows pH and temperature together on a backlit LCD. A stability symbol helps you choose when to read, while calibration indicators show completed points. Its protective silicone sleeve, folding stand and IP57-rated instrument enclosure suit a combination of field and tabletop work. The glass sensing end still needs careful handling, and the electrical connectors must stay clean and dry.

Calibrate for the samples you measure

Automatic buffer recognition supports one to three calibration points with selectable USA or NIST series. Begin with pH 7.00 in USA mode, then add fresh acidic or alkaline buffers appropriate to the expected sample range. The meter offers selectable stability criteria and electrode slope information. Automatic recognition does not make old or contaminated buffer suitable for calibration.

Know what this configuration supplies.

Direct checks across a growing area

Measure prepared, moist soil at several locations using a consistent routine. The electrode manual recommends three to five measurements and an average. Keep individual results as well as the average so that differences across the area remain visible; one convenient spot may not represent the whole site.

Collected soil and slurry comparisons

Use the documented slurry procedure when controlled sample preparation is more useful than direct field contact. Keep the soil-to-water ratio, mixing, settling and temperature consistent. Label direct measurements and slurry measurements separately instead of treating the two procedures as interchangeable.

pH-focused growing decisions

Use soil pH as one input to growing-media assessment and follow-up testing. This kit does not measure moisture content, nutrient concentration, conductivity or fertility. Wetting the soil supports electrode contact; it does not turn the instrument into a moisture meter.

Prepare the pathway.
Choose direct soil or slurry.

Connect the blue BNC pH plug and black RCA temperature plug. Remove the storage cap, rinse with distilled or deionized water, and perform at least a two-point calibration when connecting a new electrode. Use fresh buffer portions and rinse between solutions to limit contamination. Keep the sensing end within its 0 to 80°C working range.

For direct testing, the LabSen 553 manual calls for removing about 2 inches of topsoil and ensuring that the soil is wet. If dry, moisten with distilled or deionized water; ideally wait 24 hours. Use a separate dibber to prepare a pathway about 4 to 6 inches deep. Insert the electrode gently into the prepared opening without excessive force. That pathway depth is a preparation instruction, not a certified electrode insertion-depth rating.

Wait for the reading to stabilize, then record pH and temperature. Rinse thoroughly after each location, using a soft brush for adhering dirt when necessary without scraping the glass. Repeat at three to five locations and calculate the average. Record where and how the soil was wetted; no universal stabilization countdown applies to every soil.

For slurry testing, collect and mix soil from different locations at approximately 6 inches depth after removing the top layer. The manual suggests air drying or drying at 40°C. Weigh 20 g soil into a jar and add 100 g distilled or deionized water. Shake for 5 minutes or stir for 15 minutes, then leave overnight. Mix again the next morning, settle for 15 to 30 minutes, and measure the soil solution until stable.

No reference refill.
Keep the sensing end hydrated.

LabSen 553 is non-refillable. Its polymer electrolyte is inside the electrode; the 3M KCl in the storage cap is an external soaking solution. Do not open the electrode or attempt to add liquid to the sealed reference. Non-refillable does not mean maintenance-free: cleaning, calibration and wet storage remain necessary.

After testing, rinse away soil and return the measuring tip to a clean cap containing 3M KCl. Replace storage solution if contaminated or insufficient. Never store the electrode in purified water, and avoid prolonged dry exposure. The manual notes that a small amount of polymer may swell and ooze during KCl soaking; follow its instructions for gently removing that material.

Keep plugs clean and dry and inspect the glass, junction and cable before a session. If readings become slow or inconsistent, check sample preparation, storage condition and fresh calibration buffers before deciding the probe has failed. A damaged spear must be replaced, not forced back into service.

A stable reading is the start of the record.

Use the physical controls for on-meter measurement and calibration. HOLD temporarily locks a reading on screen; write the result and its sample context in your external worksheet or record system. Screen values in photographs are illustrative, not sample results.

Use calibration solutions and settings appropriate to the parameter and fitted electrode. 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.

Read the display.
Build your own sample record.

PH850 is a direct-reading instrument. Reading memory, stored content and output are not specified for this Value-series model. Build a separate notebook or spreadsheet workflow rather than expecting stored history, timed logging or a meter download.

The stability symbol and optional automatic HOLD have different jobs. Stability indicates that the displayed reading has settled under the selected criterion. HOLD freezes a stable display for transcription; it does not create a saved sample record. Release HOLD before checking the next sample.

For soil records, add location, direct-versus-slurry method, wetting history and the preparation ratio where applicable. Keep the individual measurements behind an average and note any unusually slow response. The electrode manual’s conditional reference to an M+ button does not add memory to PH850.