ORP Calibration Solution 200mV

The ORP Calibration Solution 200mV is a stable quinhydrone-based or ferric/ferrous ammonium sulphate reference standard providing a fixed 200mV oxidation-reduction potential at 25°C. ORP probes must be calibrated against a known reference solution to correct for electrode drift and surface contamination, as platinum ORP electrodes are sensitive to fouling from organic compounds in aquarium water.

The 200mV reference point sits at the lower end of the typical aquarium ORP range, making it particularly useful for freshwater systems where ORP targets 200–300mV. For marine reef systems targeting 350–450mV, the calibrated meter reading is extrapolated from this single-point calibration.

The solution is supplied in a 250ml bottle providing numerous calibrations. The shelf life after opening is typically 6 months when stored sealed and refrigerated.