DIY Fish Tank CO2 Diffuser

In this DIY, I will be showing you how to build a CO2 Diffuser for planted aquariums. A CO2 diffuser diffuses the CO2 into microscopic molecules and bubbles of CO2. The plants in aquariums need CO2 in order to photosynthesize in the water. Although fish and other organisms produce CO2, there's not enough in the water to provide adequate carbon dioxide for the plants.

This diffuser is simple and yet effective and will provide your plants with a healthy source of carbon dioxide.

The materials needed in order to build this diffuser are:

A 2 liter soda bottle with cap
1/4 diameter vinyl airline tubing
1/4 diameter valve
A small power head (used the power head from a small sponge filter)
A plastic cone/container (the longer the better)
A drill
Silicon/hot glue
Check valve

First we'll start off with the 2 liter bottle. Drill a hole into the cap of the bottle, that’s big enough to snugly hold the airline tubing. Next seal both sides of the cap near the airline tubing with silicon or hot glue (I used hot glue because the silicon kept coming off). Now cut the airline tubing about two inches away from the cap. Fit your valve and make sure its snug. Next, measure out the appropriate length of airline tubing that will connect to the other end of the valve and lead into the tank. When you have finished measuring, cut the tubing and attach one end to the remaining end of the cut off valve (adding a check valve is optional but highly recommended to prevent back siphoning). The other end of the airline tubing will connect to the plastic container or tube. Drill a hole near the edge of the top of the plastic container. Push the airline tubing into the hole and seal. Next drill another hole for the end of the power head and seal. Now place the diffuser in the tank and make sure the seals are working correctly. If your diffuser is sealed correctly then tilt the container so that the opening is facing down and make sure that there is no air inside the container. Your diffuser is now complete!

My finished diffuser

In order to produce CO2 we will need the following:

Yeast
Sugar
Water


The CO2 is created by the yeast germs in the 2 liter bottle. The yeast consumes the sugar in the water and then respirates, creating CO2. The CO2 is then forced through the airline tubing and into the plastic "chamber". In the chamber, the water in the tank and the water being forced into the chamber via the power head, mix the CO2 into the water and into smaller bubbles. Because CO2 is less dense than water, it wants to rise to the surface, but the top of the container keeps the CO2 inside. Thus, the CO2 is mixed and only the small bubbles and molecules escape and are released into the water to help perform photosynthesis.

The exact measurements vary from person to person, but my recipe will create about two to three weeks of CO2. The materials required include:

Two cups of sugar
About four cups of water
A tablespoon of yeast

First fill the 2 liter bottle with two cups of sugar. Then mix in about four cups (or until three inches from the top of the bottle) of luke warm tap water. Next add about a tablespoon of yeast. Shake the mixture well for about ten seconds. Now place the cap that leads to the diffuser, on the bottle. In about two hours, if made correctly, the yeast should start producing CO2. If after four hours, there is no CO2 being produced, warm the bottle in a bath of warm water. DO NOT MICROWAVE. THIS WILL KILL THE YEAST!

My yeast mixture

In about a week or so the plants should be flourishing. If not then there are other factors that may be effecting the photosynthesis such as the lighting, how much lighting, water quality, and water temperature.



HAPPY FISH KEEPING!