The PinPoint ORP Monitor will measure the ORP (oxidation-reduction potential, or REDOX) of your system. It’s well-liked by people who use ozone gas or potassium permanganate as an artificial oxidation agent in fresh or saltwater. Constant monitoring of the ORP comes in handy in keeping tabs at the overall health of a system, as a drop in ORP continuously precedes visual or other indications of trouble. Many serious marine enthusiasts who don’t use ozone gas use this meter to pass judgement on the overall health in their reef systems. This unit includes a 1mV digital resolution and a platinum electrode. The range is ?2000 to +2000 mV.