# Sponge Filter..



## MRQuad (Jul 13, 2008)

guys, i want to make my own sponge filter, but don't know how to do it.. can anyone help me? or post some link that i can read? thanks guys..

i tried the search button but didn't give me any good result.. thanks again..


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## Tyyrlym (Jun 1, 2008)

It's relatively simple. Here's what you need.

Materials:
Air pump - Doesn't have to be huge but you don't really wanna skimp here and get the smallest.
Air stone - Look for the coarse kind. Fine bubbles are not going to work as well as medium to large ones.
Air tubing
Check valve - Always, always, always have a check valve in your air lines. Most of the time the best place for your airpump will be below the water level in your aquarium and if it is when the power goes out it will siphon water out of the aquarium and into your pump, destroying it.
Uplift tube - The clear plastic kind, often sold for undergravel aquariums. It needs to be larger than your airstone so that the stone fits in, but not too much larger.
Sponge - This is highly variable, some shops sell sponges that already have a cut out for a tube, others don't. Make sure whatever you do get is untreated and safe for aquariums. You also want the coarse kind, not a fine sponge.

Tools:
Scissors
Drill
Tweezers
Aquarium silicone (optional)

Procedure:
1) Cut out a hole in the sponge. Do not cut all the way through the sponge. Try to leave as much thickness on the bottom of the hole as there is laterally through the sponge from the uplift tube. This will prevent water from short circuiting the path through the sponge.
2) Make holes in the portion of the tube that goes in the sponge. Again, you want to leave some distance between the last hole and the top of the sponge to prevent short circuiting. Drill, cut, or punch as many holes as you can. This is where water will be pulled in through the sponge so just leave enough tube to keep it structurally sound.
3) Insert airstone. There are two ways to do this, the first is just to drop the stone down the tube. The second way, and the one I'd prefer, is to insert it through the side of the tube. Drill a hole in the tube above the level of the sponge. Make the hole slightly smaller than the diameter of the airline tubing. Now poke the tubing through the hole and pull it through. You'll probably need tweezers or something to reach it. Making the hole slightly smaller than the tubing should seal the hole. If you're paranoid you can silicone it after finishing the filter. Now attach the air stone to the tubing. 
4) Attach the sponge to the uplift tube and adjust the airstone to make sure it sits or hangs just above the sponge.
5) Install the check valve. Run the tubing up out of the aquarium and install the valve on the section of tube running down to your pump.
6) Hook up the airline to your pump and fire her up.


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## Oldman47 (Sep 7, 2007)

Another approach that is used is to cut the top off of a plastic bottle. Stick a piece of PVC with some holes in the side of the tube down to the bottom of the bottle. Fill the space around the PVC part way up with gravel that is coarse enough not to go through the holes. Put the filter media of your choice on the top of the gravel to top off the bottle. When you run an air line down into the tube, the bubbles will draw water up the tube. That makes the water in the surrounding gravel enter the tube to be replaced by water moving down through the media and the gravel bed. The end result is a functioning filter that can be capped with a sponge, filter floss or whatever media you wish.


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