How to Set Up an Aquarium CO2 System

Providing Carbon Dioxide (CO2) to a planted aquarium is essential for the health and growth of all plants. Plants require CO2 to Photosynthesise, the process where they convert light energy into sugars that they use for growth. If your planted aquarium is not receiving enough CO2 then the plants will suffer and the water quality will degrade quickly. The good news is that you can easily set up a DIY system to supply sufficient amounts of CO2 for all types of planted aquariums.

Plants receive large quantities of Carbon Dioxide in the wild from substrate agitation and decaying plants. Unfortunately tap water is already depleted of CO2, which means that supplemental CO2 is required to allow the plants to thrive. It is easy to rig up a system with some soda bottles and household chemicals, and the results are very effective.

This method of supplying CO2 uses a reaction by product of Yeast and Sugar to produce the gas. It is a very simple setup to put together and works extremely well for 1-30 gallon tanks. For larger aquariums, multiple DIY bottles are required to increase the CO2 output.

A bubble counter is recommended to monitor the rate at which the CO2 is being released into your tank. A small needle valve is also used to alter the flow of CO2 into your aquarium. Ideally, you should aim for the drop checker to be green in colour, this indicates that there is a high level of CO2 in the aquarium which will promote growth. However, every tank will require slightly different rates of CO2 injection so you will have to experiment a little to find the right amount of CO2.

A tube is needed to connect the regulator and the reaction bottle, this should be suitable for use with aquarium air, i.e. CO2. Tubing is available from most aquatic outlets or online. The best tubing is the type that comes on the end of a syringe, this will have a very narrow opening at the nozzle and therefore can be more accurately controlled to release CO2. We recommend that you add a ‘check valve’ inline with the syringe tubing, this prevents water siphoning down the tubing from the aquarium into your regulator and possibly damaging it.