Abstract: This invention relates to a protozoan marine life inhibitor system for use with a marine aquarium. The system includes first, second and third conduits, a pump and an electrolytic protozoan marine life inhibitor unit. The first conduit is in communication with water in the aquarium and the pump. The second conduit is interconnected between the pump and the electrolytic protozoan marine life inhibitor for delivery of water from the aquarium through the first conduit, the pump and the second conduit to the electrolytic protozoan marine life inhibitor unit. The third conduit is connected to the electrolytic protozoan marine life inhibitor and is positioned to receive and return water to the marine aquarium. The electrolytic marine life inhibitor includes an alternating current power source and a pair of spaced apart electrodes electrically connected to the alternating current power source.