CO2 gas can be utilized in freshwater and saltwater aquariums. In a saltwater aquarium, CO2 can be used to dissolve calcium media in a calcium reactor. In a freshwater aquarium, CO2 can be utilized by aquarium plants during photosynthesis. The additional CO2 greatly encourages plant health and growth in a heavily planted aquarium. A CO2 reactor mixes CO2 gas with aquarium water.
