The Coralife Turbo-Twist 6X 18 Watt UV Sterilizer is for tanks up to 250 gallons.18 watt compact fluorescent UV lampMinimum flow: 200 gph. Maximum flow: 400 gph.In line or hang-onConnections: 1" or 5/8" ID hose barb. You'll need at least four feet of clear hose.Requires pump--we recommend the Rio 600Dimensions: 13" X 5"User Manual (pdf file in new window)