Milwaukee MA9020 | ORP Calibration Solution

The Milwaukee MA9020 is a lab-grade ORP solution with a certified value range of 200–275 mV, used to verify the health and accuracy of ORP electrodes and meters. Unlike ORP Standard Solutions — which provides a single fixed-point calibration reference — the MA9020 serves a different purpose: it is a quick-check solution that confirms an ORP electrode is responding correctly within an expected millivolt range. If the electrode reads within 200–275 mV when immersed in the MA9020, it is performing accurately; a reading outside this range indicates the electrode needs attention. This makes the MA9020 the routine maintenance tool for ORP electrode health verification.