Ista CO2 Controller w/ Solenoid, Bubble Counter & Check ValveThe Ista CO2 Controller with Solenoid, Bubble Counter & Check Valve is ideal for use in any freshwater planted aquarium with a CO2 injection system. This controller will ensure that your lush aquatic paradise will be accurately and reliably dosed with CO2 to promote the healthy, robust growth of your plants. Including a dual gauge with an easy to read display, you can rest assured knowing exactly how much CO2 is entering your aquarium, and how much is