APERA INSTRUMENTS / SX610 / AI221

A slim pH tester.
A simpler routine for small vessels.

SX610 brings one-button pH measurement to aqueous samples. Its 10 mm diameter SX615 probe reaches into suitable narrow vessels, with automatic pH 7.00 calibration. The AI221 kit includes ready-to-use calibration buffer, storage solution, CR2032 batteries and a carrying case.

Choose SX610 when 0.1 pH resolution and single-point calibration suit your method. Accuracy is ±0.1 pH, ±1 digit. Check vessel opening, sample depth and clearance: a slim probe does not guarantee every tube will fit.

A narrow sensing end, not a universal fit

SX615 combines a glass pH bulb with a built-in temperature sensor. Its 10 mm diameter is the probe dimension, not a minimum tube bore. Allow clearance around the sensing end and avoid contact with the vessel wall or bottom.

Calibration with one button

CAL starts automatic recognition of pH 7.00. A stable-value reminder helps you decide when to read. This model has one calibration point, not two or three; its 0.1 pH display increments are not hundredth-pH performance.

Replace the sensor when performance declines

SX615 is a model-specific replacement module, not a cabled laboratory electrode. The exact US sources do not name a standard connector. Match model and SKU instead of selecting by appearance, then recalibrate after replacement.

Know what this configuration supplies.

Test-tube teaching exercises

Compare compatible aqueous samples in suitable narrow vessels. Secure the tube and immerse the sensing end. No numerical minimum immersion depth or sample volume appears in the checked US documents; do not assume microliter capacity.

Routine water-solution checks

Manufacturer applications include hydroponics, pools, spas and water treatment. Check that SX610 meets your method’s accuracy requirements. A pH value alone does not describe nutrient strength, disinfection effectiveness or overall water quality.

Small-batch comparisons

Use clean containers and compare solutions at similar temperatures. Rinse between samples to limit carryover. Replace an aging sensor when cleaning and calibration no longer restore acceptable response.

Start with pH 7.00.
Let the reading settle.

Remove the cap, rinse with distilled water and gently remove excess water. Immerse the sensing end in clean pH 7.00 buffer. Stir gently, then hold still until the reading stabilizes. Keep the glass bulb clear of the container bottom.

Press CAL for about two seconds until CAL appears. The value 7.0 flashes while calibration finishes, then measurement resumes. Replace contaminated buffer and never return used portions to the supply bottle. Only pH 7.00 is documented for automatic recognition.

Rinse again before measuring your sample, stir gently and wait for a stable reading. Automatic temperature compensation is specified at 0 to 60°C on the US meter page, but the exact SX615 page rates the probe at 0 to 50°C. Keep use within the narrower probe rating unless Apera confirms otherwise for your supplied unit. ATC does not remove temperature-related changes in the sample itself.

Protect the glass.
Keep storage solution separate from buffer.

After measurement, rinse the probe and replace its protective cap. The exact manual recommends a little supplied storage solution in the cap. The kit specifies 3M KCl, which maintains the probe between uses; it is not calibration buffer.

For contamination, the manual describes gentle cleaning around the bulb with a small soft brush and soapy water if necessary, then distilled-water rinsing. Avoid abrasives. Recalibrate after cleaning, allowing the recovery time described in the manual.

Err or persistently poor accuracy or response can indicate replacement is needed. Check buffer and cleanliness first. Sensor life depends on care, not warranty length. IP57 does not permit unrestricted chemical exposure or prolonged submersion.

Read the scale. Check calibration.

Use the controls only for the measurement and calibration functions documented for this exact tester. Check the displayed value, unit and any documented calibration indicator 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.

Follow 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.

Read the result.
Write down the sample context.

Record settled pH, sample identity and calibration checks. No measurement-memory function is documented. A stability reminder is not a stored result, and the exact US guide does not establish a separate hold function.

Automatic shutoff follows 10 minutes without operation. A low-battery indication prompts replacement of the CR2032 cells. Manufacturer screen photographs show example values, not results from your samples.