APERA INSTRUMENTS / PC850 / AI5514

Two sensing heads.
One portable water-testing kit.

Measure pH, conductivity and calculated TDS with the PC850 and two separate temperature-sensing electrodes. The 201T-F handles pH; the 2301T-S handles conductivity. A clear LCD and automatic calibration support field and bench water checks, with results documented in your own record system.

Choose catalog AI5514 when you need pH and EC/TDS in one portable kit without a data-logging workflow. Connected electrodes do not mean pH and conductivity appear together: select the measurement mode and read its value alongside temperature.

Two electrodes, distinct connections

201T-F connects through BNC for pH and RCA for temperature. 2301T-S uses an 8-pin connection for conductivity and temperature. Each is replaceable. The supplied clip holds the pair; this is not one combined pH/conductivity sensing head.

Make EC and TDS comparisons meaningful

The platinum-black K=1 conductivity cell supports a broad working range. Set a TDS conversion factor from 0.40 to 1.00 for your method; TDS is calculated from conductivity, not a separate direct chemical measurement. Record the factor and reference temperature when comparing results between instruments.

A practical field display

The LCD pairs the selected measurement with temperature and shows stability and calibration icons. Optional automatic hold helps with transcription. The IP57 instrument, protective sleeve and folding stand suit field-to-bench work, but connectors still need protection and both sensing ends need appropriate care.

Know what this configuration supplies.

Process-water spot checks

Track pH alongside conductivity in compatible water-treatment and process samples. Standardize sampling and temperature-compensation settings so changes in the method do not masquerade as changes in the water.

Hydroponic solution checks

Use pH for acidity and EC as an indicator of dissolved ionic content in general nutrient solutions. TDS depends on the conversion factor; it does not identify individual nutrients.

Environmental and teaching work

Compare suitable water samples using two clearly separated measurement methods. Very low-conductivity water and concentrated chemicals may need a different electrode or method.

Calibrate each channel.
Record each selected mode.

Connect both 201T-F leads and align the 2301T-S 8-pin plug before securing its ring. Remove the protective bottles, rinse the sensors and keep their storage liquids separate. Select pH or conductivity as required. Both electrodes can remain connected, but select and document each parameter separately.

Begin pH calibration with pH 7.00 in the USA series, then use additional buffers around the sample range. For conductivity, use fresh standards near the intended range and set the cell constant to K=1 for the supplied electrode. Rinse between solutions; wait for the stability indication before confirming calibration.

Immerse the relevant sensor fully enough to wet its sensing surfaces, stir gently to release bubbles and wait for a stable value. Capture the displayed unit: µS/cm and mS/cm differ by a factor of one thousand. Use the supplied conductivity probe within the 0 to 50°C compensated measurement range.

Different sensors.
Different storage liquids.

The 201T-F has a sealed gel reference that is not refillable. Keep its glass bulb and junction wet in the external bottle using Apera 3M KCl storage solution, AI1107. Replace contaminated liquid. Pure water is suitable for rinsing this pH probe, not for long-term storage.

The 2301T-S instructions specify distilled or deionized water in its storage cap. Rinse before and after testing and replace contaminated cap water. Do not transfer the pH probe’s KCl storage solution to the conductivity cap. Avoid rubbing the conductivity sensor or damaging its platinum-black coating.

Keep connectors clean and dry. Remove residues with compatible gentle cleaning, then rinse and recalibrate. Protect the polycarbonate pH housing from aggressive solvents. A damaged or persistently unstable electrode should be assessed or replaced rather than corrected by an arbitrary offset.

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.

Build a paired sample record.

PC850 lists data storage and storage content as not applicable. There is no stored sample history to recall. Automatic hold freezes a displayed reading temporarily; it is not a logger. USB export, PC-Link and Bluetooth are not documented features of this Value model.

For each sample, record its identifier, observation time, pH and temperature, then conductivity with its unit and temperature. If reporting TDS, also record the conversion factor. Add the conductivity reference temperature and compensation coefficient to document the method.

Check the paired entries before moving on. Note calibration standards and unusual sample conditions. Supply dates and times yourself; do not assume the meter creates timestamped files or that a photograph automatically preserves the method settings.