CO2 is used to enhance growth of plants in the aquarium. Plants are about 50% carbon so adding CO2 is like giving them jet fuel. They become more radiant and full of life. You’ll definitely notice the difference once CO2 is added to the aquarium. All planted tanks can benefit from adding CO2 to the water, even if just a little bit. The photosynthesis process is quite simple, the brighter the light, the more CO2 your plants are able to absorb and the faster they will grow. With lower lit tanks, plants will still absorb the CO2 but growth rate will be slower. Select from our range of products below.