Pro Elite Series Advanced Aquarium Dual Stage Extendable CO2 RegulatorCO2 systems for planted aquarium tanks by Co2Art. Turn your aquarium into a natural beautiful piece of art! For aquascapers that want to keep multiple aquariums under the control of one system. CO2 is arguably the most important element in the planted aquarium. It is required for respiration and growth by all aquatic plants, used in a process called photosynthesis. Plants require a constant supply of CO2 during the light hours, otherwise they can