The Phosban Reactor 150™ has become a staple amongst most aquarists who keep SPS corals. So much so that you often see Phosban used interchangeably with the term GFO or Granular Ferric Oxide. It can be mounted hanging on the back of the aquarium or below the aquarium. Includes ball valve for regulating flow, and flexible connection fittings that rotate 180 degrees to allow a perfect custom fit to your installation. The threaded lid design makes servicing quick and easy. One reactor for aquariums up to 150 gallons.