Aquarium Plants & Carbon Dioxide

The Key to Lush, Vibrant Plant Life!

Carbon Dioxide is a very important nutrient for plants. It is used to form the basic carbon structures that all plant material is made out of. If you have excellent lighting, but aren't experiencing the lush growth you had expected, it is probably due to a lack of CO2! The more light you give your plants, the more carbon dioxide they will require, and the normal amounts provided by fish and other sources just won't cut it!

The ideal level of CO2 for plants is 8-10 parts-per-million. You can test your levels with a simple CO2 test kit. If your tank is not providing your live plants with the proper CO2, there is a simple way to correct the deficiency.

Carbon Dioxide is water-soluble. In a Carbon Dioxide Reactor, your water is injected with the gas and slowly released back into your aquarium. A Reactor is relatively easy to use. Most are long tubes that fill with your aquarium water. The CO2 is usually in an easy-to-use cartridge. The CO2 is injected into the reactor where it quickly dissolves into the water. The water is then pumped slowly back into your aquarium.

pH and KH are two factors that will contribute to the success of your Carbon Dioxide reactor. The system will work best in a pH of about 6.8 to 7. The ideal KH is 90 ppm. If your KH is at the appropriate level, the slow addition of the CO2 will also lower your pH. Be sure to test your pH and KH regularly when dosing CO2.

Carbon Dioxide Q & A

Why do I only add CO2 when the lights are on?

Plants only use CO2 when light is available. At night, they actually use Oxygen, so if you need to, turn on an air stone at night to make sure your tank is nicely oxygenated.

Can I run an air stone during the day with the CO2?

By oxygenating your water, the CO2 will be able to escape out the top of your tank and into the atmosphere more quickly than your plants are able to use it. So it is best to only run an air stone when you are not adding CO2.

Can I add too much CO2?

Too much CO2 creates carbonic acid. This can lower your pH to an extremely low level, so watch your pH carefully when dosing CO2.