The Fishies KW Reactor 300 is a highly efficient calcium reactor designed for saltwater aquariums. It uses the upflow principle to mix top-off water with calcium hydroxide, creating a supersaturated kalkwasser solution automatically. This innovative design not only saves time but also ensures consistent calcium and alkalinity levels in your reef tank without manual adjustments. The KW Reactor 300 is conveniently mountable both above or below the aquarium, featuring a ball valve for flow regulation and flexible fittings that rotate up to 180 degrees for easy installation.