Things You'll Need
- Soda bottle, clean
- Small hand saw
- Hot fork
- Toilet overflow pipe
- Sponge
- Scissors
- Aquarium tubing, enough to reach from the bottom of the tank to the aquarium air pump outside the tank
- Gravel
- Filter wool
- Air pump
Instructions
Take the clean soda bottle and cut it horizontally approximately 3 inches from the top of the bottle using the hand saw. Take care to make the cut straight.
Using the hot fork, make holes in the top of the soda bottle, by the neck of the bottle. Do not make holes in the body of the soda bottle as it will then leak and be ineffective. Make at least 12 sets of holes.
Place the top of the bottle inside the bottle. This should be a snug fit.
Cut the toilet overflow pipe so that it is approximately an inch higher then the body of the soda bottle. Place it snugly in the neck of the bottle, but do not press it all the way down. You want water to be able to flow up the pipe.
Cut a piece of the clean sponge to fit the inside of the toilet overflow tube. Place the aquarium tubing inside this sponge and thread it down the tube. The sponge will hold it in place.
Add gravel to the filter, filling it two-thirds of the way. Top this with filter wool. This can be pressed down gently in order to make it stay. It may need to be pressed down again once in the water.
Place the fish tank pump in the aquarium and hook the loose end of the aquarium tubing to the air pump. Air bubbles should form shortly after turning the pump on.