Ultralife Ultra-V VHO UV Sterilizer 16 watt 16 Watt UV Unit 430 gph 40 Watt UV Unit 1000 gph 60 Watt UV Unit 1500 gph UL&gt;By changing the flow rate through the UV unit you will change the effect Waterborne Algae 15,000 to 30,000 W sec/cm2 Common Bacteria 15,000 to 30,000 W sec/cm2