Sera Flore Active CO2 Reactor 500 - Small 66-160 Gal Top range performance CO2 reactor for complete dissolving of CO2 For internal or external mounting to water pump (Hose size:OD 5/8" ID 1/2") Dissolves 500 to 1000 CO2 bubbles/min depending on model Features easy installation and cleaning Made of acrylic with brackets, suction cups and hose connectors with fastener