Parameter / ORP 


The Oxidation-reduction potential, ORP in short, is a measure for the concentration of oxidizing and reducing agents in water. Its value is influenced both by pH and temperature. ORP is a sum parameter that gives no information on the concentration of a single substance in a mixture.



ORP measurements are used to monitor chemical reactions involving electron transfer. In drinking water treatment it can be found in Ozone treatment and the removal of iron, manganese, and nitrate as well as in disinfection steps. In swimming pools the German DIN 19643 requires ORP measurements as a hygiene parameter and decrees maximum and minimum values for fresh water, pool water, and salt water. In waste water treatment ORP is measured in the denitrification process and in detoxication of industrial waste water.


Dr. A. Kuntze measurement

The ORP sensor consists of a measuring electrode of platinum or gold and a reference of Ag/AgCl. The potential of the measuring electrode changes with the concentration of reducing and oxidizing agents and is measured against the reference. The measured values can be recalculated to fit literature values based on NHE (normal hydrogen electrode) as reference.  


You would like to measure ORP in your application?

Select one of our measuring instruments– either you choose our single-channel instrument series K 100 or our two-channel instrument series dialog. Therunto one of our high-quality ORP-sensor , a immersion or flow assembly  and our sensor cable

measuring point - flow
measuring point - immersion

Since 1945 we are developer and manufacturer of sensors in Germany. In our sensor production in Meerbusch we produce pH, ORP, conductivity, and disinfectant sensors.


Our sensors are useable in all different types of application: ultra pure water sensors, specially designed process sensors, and dirt and poison -resistant sensors for industrial waste water.

Highly sophisticated

For our sensors we rely on premium materials and best processing. Our metal electrodes e.g. consist of gold or platinum with a purity of 99,99%.