pH probes are sensitive equipment that should be given extreme care. They should not be subjected to knocks, extreme temperatures or corrosive chemicals.
Some tips for ensure maximum lifespan and accuracy.
Never allow glass probe to be dry either in storage or in use.
When the probe is dry, dissolved solids in the water will settle on the surface of the glass probe and “eat” into the glass causing inaccuracy or even kill the probe.
Never store the glass probe in tank water, tap water or deionised water.
These water are full of contaminants or very corrosive and prolong exposure to them will result in these contaminants coating the surface of the glass probe. Always store the glass probe submerged in potassium chloride solution or at least in pH7.00 calibration fluid.
Never calibrate with other fluids except the proper calibration fluid.
The readings on the pH meter is based on the calibration fluid accuracy. Most calibration fluid have an accuracy of at least pH0.001. If you use other fluids other than the proper one, you are introducing more errors into the readings.
E.g If the actual pH of a solution is pH6.5 but its stated as pH7, you try to calibrate the pH probe based on the written pH then the pH probe will be +pH0.5 off the actual pH. Every other readings later on will have an error of pH0.5.
Proper way to store a pH pen
Wash glass probe under tapwater after use
Flick the glass probe to get rid of excess water
Pour some pH7.00 calibration fluid in the cap
Replace the cap and ensure that some fluid overflowed. This will ensure that the glass probe is fully submerged.
Try to use the probe at least biweekly, this is to ensure that the calibration fluid wont get completely dry and promote pH monitoring
Using pH pen
Switch on the pH pen and give it a few shakes
Ensure reading is correct at pH 7.0. If reading is inaccurate, pour more calibration fluid into the cap and test again, the acceptable reading should be pH6.9 – pH7.1.
Do fine tuning to the probe
Wash it under tapwater and use
Store the probe using the proper method.