Under what circumstances does the pH meter need to be recalibrated?
The instrument needs to be recalibrated if any of the following occurs:
(1) When there is a large difference between the solution temperature and the calibration temperature.
(2) The electrode is exposed to the air for too long, such as more than half an hour.
(3) The positioning or slope regulator is accidentally moved;
(4) After measuring peracid (pH2) or peralkaline (pH12) solutions;
(5) After replacing the electrodes;
(6) When the pH value of the measured solution is not in the middle of the solution selected during two-point calibration, and is far away from 7pH.
