An aquarium filter which works by drawing water through the gravel bed at the bottom of the aquarium. The system has a filter plate which sits on the bottom of the aquarium. The filter plate has slots or holes in it that are large enough to allow water to pass through, but are small enough to prevent the gravel from falling in. A pair of uplift tubes use rising air bubbles to draw water up from underneath the filter plate.
The gravel bed has a very large surface area on which a bacteria colony can grow. This bacteria colony processes the ammonia and nitrites in the aquarium down to a set of chemicals that are far less toxic to the fish and other inhabitants.
In large aquaria, it is necessary to add a power head to the uplift tubes in order to increase water flow to a level that will circulate sufficient water in the aquarium to prevent the build-up of aquarium chemical contaminants.