Why DIY?
Pressurized CO2 systems are an expensive investment. You may not be sure it will be worthwhile, and would like to try CO2 injection to see how it affects plant growth before spending the money for a pressurized system. Or maybe you have 3 tanks in 3 different rooms, which would require 3 pressurized systems. Perhaps you are on a student budget and just can’t afford a commercial system. Or maybe you have a 50 litre tank and figure a full CO2 system would be overkill.
For any of these reasons, a DIY CO2 setup would be worthwhile. It costs very little, can be set up in a single day, and only requires a few minutes of maintenance every few weeks. And the difference to your aquatic plants can be dramatic.
So How Does It Work?
A yeast culture is started in warm sugar-water inside a closed bottle with tubing leading into the aquarium. As the yeast begins to reproduce and metabolize, it uses the sugar for energy and begins to produce CO2 as a byproduct. The CO2 builds up a slight pressure inside the bottle and then exits through the tubing into the aquarium. Various diffusers and reactors can be used to disperse the CO2 throughout the tank. The yeast culture continues to produce CO2 until all the sugar is used or until the alcohol level in the bottle reaches toxic levels.
How Do I Set Up a System?
You will need a 2L Fizzy bottle or plastic container with a screw cap which fits tightly, some standard airline tubing, and silicone glue from the hardware store.
Drill or punch a hole into the bottle cap to the approximate size of the airline tubing.I find that if you make the hole slightly smaller than the tube,it creates a tight fit and silicone is not required. Insert the tubing so that it extends 2 to 3 cm into the bottle cap. Glue the tubing to the cap on both inside and outside. Allow to dry overnight. At some point on the tubing, insert a check valve so that gas can exit the bottle but not return. This will prevent any siphoning from the tank into the bottle.
RECIPE: Using a funnel or rolled up paper, pour 2 cups of sugar into the bottle. Add 1/4 teaspoon of baker’s yeast and a pinch of baking soda. Pour in a little warm water (NOT hot) and mix around to dissolve the sugar and yeast. Then fill to the shoulder (just above the label on a soda bottle) with warm water. Shake well and cap with the tubing-cap assembly. Run the other end of the tubing into the aquarium.
This setup will serve an aquarium in the 30-150litre range.
To disperse the bubbles, you can do any of the following:
- place the tubing into or under the intake to the canister, powerhead or power filter, allowing the filter impeller to disperse the bubbles. Caution – do not place the tubing in any high flow area which might create a vacuum in the tubing and collapse the culture bottle or siphon the culture into the tank!
- place an airstone on the end of the tubing and anchor in the aquarium.
Yeast mix usually will last for two to three weeks and with the occasional swirl will continue to produce sufficient CO2 bubbles for lush growth of plants.
REMEMBER: you will need more than just CO2 to grow plants
Also required are LIGHT and NUTRIENTS
Please feel free to comment or ask advice as I use this setup and have done fore thelast 12 months or so with very successful results.
pic borrowed from internet
Simon
