How to Make Your Own Waterfall Filter

Cut one to three holes in the top of one side of a bucket, bin, or canister. This is for your inflow pipes or tubes -- the more points of contact between the water and the filter media, the better. The holes must be cut exactly to fit the pipes or tubes.

Cut one pipe-sized hole in the bottom, opposite side of the container. This is for your outflow tube or pipe. The idea is that water trickles down over the filter media, getting plenty of air for oxygenation along the way, and back out through the bottom of the container, then out into the waterfall.

Fill your container approximately 2/3 full with "hard media." This can be any number of nontoxic, non-degradable craggy objects with plenty of surface space for nitrifying bacteria to grow. These bacteria are what break down dirt and debris. It will take a few weeks for the bacteria to grow. A few possible choices for hard media are lava rock, hair curlers, chunks of sponge, steel-wool pads (soap-free), or plastic connectors for shelving cubes. There is a product made for the aquarium trade called "Bio-Balls" that serves the same purpose.

Place a layer of "soft media" at the top of your container, which is where the water is first pumped into the bin. "Filter floss" sold for fishtanks works well, or, for a cheaper option, buy polyester sheeting sold in craft stores for stuffing quilts and dolls.

Close the lid, and seal your tubes or pipes into place so that the container is leak-free as water runs through it.

Rinse your filter media often, using water from your waterfall. Tap water will kill the nitrifying bacteria in your filter that breaks down debris. When the media wear away and need to be replaced, do not replace all at once.