CO2 (Carbon Dioxide) is useful both in freshwater and marine
environments.
In the freshwater aquarium, CO2 enhances your ability to successfully
keep live aquatic plants. As green plants photosynthesize, they utilize
carbon dioxide. Without CO2, live aquarium plants will have a hard time
thriving in the closed aquarium system.
In the marine aquarium, CO2 is used to lower the pH of calcium reactors
effluent in order to dissolve hydro carbonate media into bio-available
calcium molecules. Calcium is then utilized by corals and other marine
organisms mainly for skeleton building.
