How to Build the CO2 Pressure of an Aquarium

Plants in the aquarium require carbon dioxide (CO2) to survive. Fish respiration provides some CO2 and you can inject more CO2 into the aquarium water if desired. CO2 injection systems could be expensive, but you can assemble one yourself. This system uses a generator to contain a yeast mixture that produces CO2 and a reactor to dissolve the CO2 in the water.

Things You'll Need

Two-liter plastic bottle
Drill
Air line tubing
Silicone sealant
Transparent container
Glue or sticky tape
Water
1 cup sugar
1/2 to 1 tsp. yeast
1 tsp. baking soda (optional)

Instructions

Create the Generator
- 1
  Drill a hole through the lid of a two-liter plastic drink bottle.
- 2
  Place an air line tubing of about one inch through the hole.
- 3
  Apply silicone sealant to both sides of the lid to keep the air line tubing in place.
Build the Reactor
- 4
  Find a transparent container such as a plastic cup.
- 5
  Hold the container upside down.
- 6
  Place the container partly in the aquarium, then tape or glue the section above water to the side of the aquarium. This container will collect the CO2 until it dissolves in the water.
Yeast Mixture
- 7
  Dissolve 1 cup of sugar in 2 to 4 cups of water.
- 8
  Add 1/2 to 1 tsp. of yeast to just enough warm water to dissolve it.
- 9
  Pour the sugar solution and the yeast solution into the generator. When the yeast starts to produce CO2, you will see some froth forming in the generator. You can add 1 tsp. of baking soda into the generator to minimize the amount of froth and to make the mixture last longer.
- 10
  Connect the generator to the reactor by placing the air line tubing in the reactor. Do this only when the yeast mixture has reached room temperature, because otherwise the tubing could suck aquarium water into the generator.
- 11
  Replace the yeast mixture every 10 to 14 days.