Build a Pond Filter System

Save money and the environment while building a pond filter system. It's better for the fish, too!

Steps

Find an old plastic trash can with lid. Create a drainage hole in the can, on the side near the bottom. Position the can so that run-off from the drainage hole will return to pond.
Fill the can with clean filtration material.
Submerge a waterproof pump into the pond. Run the exit pipe from the pump to the top of the filled can.
Turn on pump. Water will flow out to top of can, through filter material, back out through drainage hole and into pond.
Finished.

If you want to attach the water inlet to the bottom of your container you can find the hardware (it will be listed as a rain barrel plumbing attachment). The benefit of moving the water up, is you create height for a waterfall and if the filter plugs up you pond won't go dry. You will need to start with a container with a spout or lip, the bigger the better and use lava rock for filtration, it works great.
It is possible to make small version of this made from a plastic shoebox. Smaller version may be located in the pond, attached AHEAD of pump so that pond water is sucked through the filter, rather than poured over it.
You can alternately fill the garbage can with half clean gravel, then top with sponge filter material.