DIY Aquarium CO₂ systems and why to add CO₂ to aquariums

by Mick

CO₂ systems are added to the aquariums to enhance lush plant growth where the plants use light energy to utilise the CO₂ to promote their growth.

Several aquarists have success with their planted aquariums with installing these systems but for typical “Dutch Aquariums” these certainly play a major part in their success. How many times have we looked in magazines & wondered how on earth do they get them to look like that well hopefully this article will help to explain how they work & the choices available.

Basics of CO₂ in the aquarium:

Plants need carbon for growth as well as adequate lighting but a balance has to be reached as lighting alone will not provide ideal conditions for the plants, hence the need to bubble in CO₂ as this will provide the carbon required.

Too much CO₂ also can cause problems as this will affect the pH of the water & this will then lead to a pH crash, also bear in mind excessive CO₂ will produce carbonic acid (H₂CO₃) which is toxic, definitely not good so most systems have some form of regulator with them so you are always in control.

There are several systems on the market & if you are a bit of a DIY addict then one can be assembled with a few basic skills

Systems available:

Most CO₂ systems will incorporate a pressurized CO₂ bottle with a regulator valve which is normally set by a bubble count per minute & some of the top systems will also have a CO₂/pH controller. This is an example of the kit you require with the pressurised bottle system.

Another option is the yeast method where yeast is mixed with sugar & through the fermentation process CO₂ is produced & a bubble trap is added to the silicon piping to control the amount of bubbles released into the water. This version is produced by Nutrafin & I have personally used it myself in smaller tanks with great success.

DIY System;

I have made a system quite easily by using a 2ltr pop bottle using the yeast method, adding the yeast, sugar solution & attaching silicon airline attaching a cheap flow valve to control the amount being released into the system purely by counting the amount of bubbles per minute & adjusting accordingly (note; silicon tubing is used as the CO₂ can erode standard airline)