These filters are incredibly easy to make, very cheap and work very well. (Its also fun eating and drinking the contents of the items required
Items you will need are:
1a. An empty 4 lt ice cream container
1b. An empty 2 lt ice cream container
1c. An empty 500 gm round margarine container
The options above are dependant on the size tank you want to filter and further on, you will also notice different size soft drink bottles needed to complement the above. The following pictures were taken of the 4lt container.
You will also need:
2a and b. The neck of a 1.25lt or 2lt soft drink bottle
2c. The neck of a 600ml soft drink bottle
3. Two lengths of airline (total length to reach from the bottom of your tank to your air supply)
4. One adjustable air valve
5. Coral rubble, shellgrit, coral sand or any media of your choice keeping in mind that this filtration will also help buffer the water and will need to be cleaned/washed on a regular basis eg every 2-4 weeks. Filter wool is not recommended although filter matting can be used as a top layer.
6. An airstone (plastic candy striped ones are better than pumice - try Atlantis for some. They are invincible.)
Preparation and assembly instructions:
1. You need to punch as many small holes into the lid of the container as possible. One larger hole needs to be placed into a corner for your airline and a larger hole needs to go into the centre of the lid to be able to accommodate/suit the neck of your soft drink bottle.
2. You also need to cut your drink bottle (keep the neck end and throw away the rest) at a height/length that will sit snugly in your container and suit the lid height also. The lid should eventually sit at the bottom of the thread on the neck of the bottle as this will keep it held in place. Punch two or three rows of small holes into the base of your drink bottle and again, a larger hole closer to the neck to accommodate the airline. If you are finding it difficult to punch these holes, you can cut Vs into the edge with a pair of scissors getting a \/\/\/\/\/ effect which also works well. You can now feed your airline through the hole and add your airstone.
3. Place your drink bottle top into the centre of your container making sure the airline sits facing a corner. You can now add the media of your choice up to the base of the bottle neck.
4. Feed your airline through the corner hole in the lid and push the lid into place on your container. Locate the filter in your tank and then add your air valve (just above the lid is good) and reconnect to your air supply.
5. Sit back and relax
Remember, these are only a lightweight filter and are not designed for over populated or heavily fed tanks. Basically, they are a glorified corner filter at a fraction of the cost