How do you know when to clean sensors?
pH sensor:
pH sensors are usually very stable and predictable but also require routine calibration to your test kit reading. Calibration may be needed once a week but more frequent calibration indicates the need for cleaning.
ORP sensor:
ORP levels are based on chlorine levels and consistent pH. Be sure to clean ORP sensors at the same time as pH sensor. If you see a trend with ORP levels 30mV different than prior to cleaning, you waited too long. Adjust cleaning schedule accordingly.