DIY CO2

HOW TO MAKE YOUR VERY OWN DIY CO2

yeast diy co2 bottle make it yourself

Making your own CO2 is very easy, rewarding and a relatively short process. When creating CO2 for your aquarium you will have to take into account the size and number of bottles you will use, the recipe, the setup and diffusing.

Before beginning it is important to decide the volume of bottles your aquarium will require. For a standard size 3 foot 55 gallon aquarium, two 2L coke bottles is appropriate for producing about two bubbles per second. It is important to remember that unlike pressurized CO2 with a solenoid valve, DIY CO2 cannot be switched on and off at specific times. It is therefore important to choose a slightly lower than recommended rate of CO2 for your aquarium to avoid large unwanted pH swings.

For aquariums under 25 gallons one 2L coke bottle is more than suitable. If the tank is extremely small it could be possible to use one 1.25L bottle. However very small tanks are more susceptible to unstable conditions and CO2 dosing is easier on larger, higher volume aquariums.

Equipment Check List


  • Raw Sugar
  • Sodium Bicarbonate
  • Brewers Yeast
  • Empty Half Gallon Bottles
  • Drill with 3/16" bit
  • 3/16 " (4mm) Rubber Tubing
  • Bubble Counter
  • One Way Valve
  • Glass Diffuser or Cup
  • Super glue

Adding the Ingredients

Adding the yeast

Initial Phase

System Setup

Diffusing the CO2

Testing CO2 Levels