The Rapids Surface Skimmer Overflow efficiently skims the surface water of the aquarium, removing dissolved organics and other waste material to the filter where these contaminants and other impurities are broken down. This is the only surface skimmer that delivers automatic filter stop and start in the event of electrical power loss. This feature does not allow any aquarium water to back drain into the filter box--preventing flooding. The Overflow will handle up to 1,000 gph. The Tom Aquarium Products Rapids Surface Skimmer Overflow includes an Aqua Lifter pump.