Very easy and cheap way to make your own Aquarium sponge pump. Perfect pump for small tank, small fishes, shrimp tank, breeding tank ... Using a simple air pump and basic materials, you can create a mechanical/chemical filter for your aquarium!

Step 1: How It Works

Sorry for my very poor drawing, but the idea is there!
When air goes out of the air tube and up the wider tube, it sucks up water at the same time, so water goes through the sponge, up the tube and clean water comes out.
As simple as that!

The sponge serves as a mechanical filter holding big particles in it, and also as a bio-chemical filter. Good bacteria will grow in the sponge and clean the nasty stuff out of the water. You only need to wash the sponge with clean water from time to time.

Step 2: Materials Needed

First, Gather all equipement:
Basically, you will need a Drill, a pair of scisors, a wide tube, air line tubing & aquarium air pump For the outside (wider) tube, i use a rectangular tube i found in my garage. You can use watever is bigger than your air line tubing and that is open on both ends.

Step 3: Assembly

1. First you need to cut your sponge the size & shape that best fits your aquarium, you can go for a corner filter...
(The sponge i used is just a regular cleaning sponge so I was able to cut it with scissors. You can also go for an 'aquarium sponge' that you can find at a pet shop, you might need to cut it using a bread knife. )
2. Cut a hole in the sponge to fit your large tube in it. You don't have to go all the way through. mid-way is enought.
3. drill tiny holes on one end of the large tube to let water in from the sponge.
4. Insert Tube in the sponge (tiny holes in)
5. Plug the air line tube to air pump and insert air tube in larger tube.
6. Voilà! Make sure you wash carefully all parts of the filter before moving it in your aquarium.
To fix it inside, you can either weigh it down with a rock or stick it to the side using a suction valve.