Best Practices on caring for your pH testers – A-Grade Hydroponics

May 22, 2020 steven

Best Practices on caring for your pH testers

This tutorial is from our friends at Hanna Instruments, taken from their ‘pH Best Practices guide’.

Keep the electrode hydrated

Why — Drying out the electrode leads to drifting pH values, slow response times, and incorrect measurements.

Fix — “Revive” a dry electrode by submerging the bulb and junction in pH storage solution for at least one hour.

Rinse, do not wipe your electrode

Rinse, do not wipe your electrode Why — Wiping the pH glass can produce a static charge which interferes with the pH reading of the electrode.

Fix — Simply rinse the electrode with distilled or deionized water (DI). Blot (do not rub) with a lint-free paper towel (e.g. Kimwipes®) to remove excess moisture.

Store your electrode in storage solution

Store your electrode in storage solution Why — Storing in deionized water (DI) causes ions to leach from the glass membrane and reference electrolyte resulting in a slow and sluggish response.

Fix — Store your electrode in storage solution or pH 4.01 or pH 7.01 buffer if you do not have storage solution.

Clean your electrode regularly

Clean your electrode regularly Why — Deposits can form on the electrode during use, coating the sensing glass. This can lead to erroneous calibrations and readings.

Fix — Clean the electrode using a specially formulated cleaning solution for pH electrodes, ideally one that’s developed for your application.

Calibrate often

Calibrate often Why — All pH electrodes need to be calibrated often for best accuracy.

Fix — The frequency of calibration depends on how accurate you want to be – daily calibration is ideal.

Pick the right electrode for your sample

Pick the right electrode for your sample. Why — General purpose electrodes are functional for a wide variety of applications but not ideal for all samples.

Fix — Based on your sample you may require an electrode designed for food, high/low temp, non-aqueous, or other types of samples.

Properly submerge your electrode

Properly submerge your electrode Why — Both the pH sensing glass and reference junction need to be completely immersed in order to function properly.

Fix — Add enough sample to submerge both the junction and sensing glass.

Inspect your electrode

Inspect your electrode Why — Over time, the sensing portion of the glass becomes less responsive and will eventually fail. Damage from use is also possible. This will cause erroneous readings.