How is oxidation reduction potential (ORP) measured?

Oxidation reduction potential (ORP) is measured using specialized electrodes known as ORP probes. These probes consist of a sensing electrode that responds to the oxidation-reduction reactions occurring in the water. When the probe is immersed in the pool water, it generates a voltage signal that correlates to the oxidizing or reducing state of the water. This signal is then sent to chemical controllers, which can adjust the levels of sanitizers, such as chlorine, to maintain water quality.

This method is highly effective because it provides real-time measurements that are critical for ensuring the safety and sanitation of pool water. Maintaining the proper ORP level is vital for disinfection, as it reflects the effectiveness of the pool sanitizers in killing pathogens.

Other methods listed, such as color changes, pH tests, or temperature assessment, do not directly measure ORP. Colorimetric tests might be used to assess chemical concentrations, and pH measurements are important for overall water chemistry, but they do not provide the specific insights into the redox state of the water that ORP measurements do. Temperature variations, while relevant for understanding water conditions, have no bearing on ORP readings.