The majority of aquarists who keep SPS corals now use the Phosban Reactor 150TM. Phosban is frequently used interchangeably with GFO, or Granular Ferric Oxide, for this reason. Features a ball valve to control flow and 180-degree rotating flexible connection fittings for a flawless, customized fit in your installation. Service is quick and simple thanks to the threaded lid design. One reactor for 150-gallon aquariums.