Dymax CO2 Bubble Counter Double Ended is design for both planted & reef aquarium. For planted aquarium, it is used to gauge the amount of Co2 applied to the plants for photosynthesis purpose. As for the reef aquarium, it is used for calcium reactor which help to monitor the amount of Co2 applied so as to dissolve calcium in the water. Dymax Co2 Bubble Counter provide accurate reading of Co2 with its well designed structure and the durability of material used, to provide the success of your aquarium.