What is ORP?

Oxidation-reduction potential (ORP), commonly referred to as REDOX, is measured in millivolts of the tendency for a chemicals substance to either oxidize or reduce another chemicals substance.

Oxidation is known as the loss of electrons by an atom or ion while reduction is the net gain of electrons by an atom or ion.

Accurate ORP Sensor

How is ORP Measured?

ORP is measured by using an electrochemical ORP (REDOX) sensor. In comparison to a pH sensor, the ORP sensor is normally a combination type which contains both a measuring and reference electrode.

The measuring cell, typically a noble metal such as platinum or gold, detects changes in REDOX potential while the reference provides a stable comparison signal. ORP is expressed in millivolts and is typically a pH instrument while using the mV scale to display the readings.


Why is ORP Measurement Necessary?

ORP measurements are a cost effective method to control various processes. Chlorine, ozone, or bromine are commonly used to disinfect effectively. It is also used in process applications to control the destruction of chromate or cyanide, as well as bleach production and wet scrubbers.

Common Applications:

  • Prechlorination and dechlorination in water/wastewater treatment
  • Cyanide destruction and chromate reduction in metal finishing
  • Ozone treatment process control
  • Bleach production
  • Poultry processing
  • Fruit and vegetable washing
  • Pulp bleaching
  • Chlorine addition in commercial swimming pools & spas