HydroLogic 31051 Triton DI100 GPD Aquarium Water Filtration System Reverse osmosis membranes remove 99% of contaminants while final de-Ionization stage delivers 000 PPM water Less waste water than similar filters - 2:1 ratio Ensure your aquatic life gets the purest water possible Highest quality components, top level engineering and earth friendly design 100 GPD rating