ORP

Definition

ORP is a bulk measurement in millivolts of water’s net tendency to oxidize or reduce, an indicator of the overall redox environment.

It is good for confirming oxidizing versus reducing conditions, trending oxidizer feed response, and indicating whether a system is strongly oxidizing for bio-control or reducing because oxygen is scavenged. It is not a direct corrosion rate measurement, not a guarantee of safe metals, and not a substitute for residual chlorine or bromine testing. It measures net redox tendency, not the rate of any specific reaction.

Related concepts

Residual oxidizer · Oxidation potential as driving force · Standard reduction potential

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Part of The Blueprint of Water · 📏 measurement