This pump is unique to the market! This filter pump has been designed to be able to provide a variable flow of water from 9,300lph to 19,800lph and it has a variable power output from 187 watts to just 34 watts!. The ability to control the flow has a number of uses: - Spectacular waterfalls can taken on a number of appearances - waterfalls can be made quieter during darkness - Flow can be reduced during winter - Flow can be increased as your pond or fish stocks grow! Important: The pump can only be ran dry on or below the water level.