hey duayne , there is no pump that pumps water, only an air pump, no filtration, thus no current for the shad to constantly swim in stressing them and knocking the scales off as they rub the sides of the tank and each other. just heavily oxygenated water. the shad keeper water conditioner takes care of the ammonia. for 25 years we worried about pumps, filtering and the right amount of circulation, seems odd but thats what was causing alot of problems to begin with. another guide researched this and did the footwork, i cant take credit for it, but it has made life alot simpler.