When calibrating a pH meter and experiencing unstable readings, what is the recommended action?

Examining the reference electrode junction for salt crystals is a critical step when faced with unstable readings during pH meter calibration. Salt crystal buildup can obstruct the ion flow necessary for accurate pH measurements, resulting in fluctuating or unstable readings. By ensuring that the reference electrode junction is clean and free from obstructions, one can restore accurate functionality to the electrode and thus improve the reliability of the pH measurements.

This approach focuses on maintaining the operational integrity of the measuring equipment before considering more disruptive actions like recalibrating or moving electrodes to a different meter. Addressing issues with the electrode directly is often the most effective way to resolve calibration instability without introducing additional variables into the process.