Chemtrol® CH230 Digital ORP Controller with Sensor, 110V, 230V or 24 VAC Polystyrene Cabinet. The CHEMTROL® 230 ORP Controller is a simple, easy to use controller designed to monitor and maintain the Oxidation-Reduction Potential (ORP or Redox) of neutraltype sanitizes such as bromine or dichlor - that do not require pH control. For complete peace of mind, proven reliability and performance, the CHEMTROL® CH230 is a fully automated "set and forget" chemical control system. Designed to maintain the sanitizer ORP (oxidation-reduction potential or Redox) level in high-end residential pools, small commercial pools and spas and light industrial applications.