pH4 Calibrating Solution is suitable for all makes and models of pH pens and meters.
pH4 Calibrating Solution is easy to use!
Just dip your electrode into a small amount of the buffer and adjust the meter to read 4.0.
Do not reuse solution.
The characteristic of a pH electrode will change with time due to electrode coating and aging. And even a pH electrode would be stable over time, pH electrodes cannot be produced with identical characteristics.
In practice the response of a real pH sensor does not exactly follow the Nernst equation. This difference between the theoretical and actual behavior of a pH electrode must be compensated for. A calibration is required to match the pH meter to the current characteristics of the used pH sensor
The main factors that degrade the performance of an electrode are coating, contamination and aging. How often you need to calibrate your electrode depends mainly on these factors and, of course, of the accuracy you require from your measurement.