What are diatom filters for aquariums?

Diatom filters remove small particulate matter, debris and parasites from aquarium water, greatly improving water clarity and the health of fish and other aquatic life. Diatom filters are used for occasional water quality maintenance only and are not meant for everyday filtration.

Diatom filters use a filtration media called diatom powder. This powder is made from a particular kind of soft sedimentary rock that is formed from the fossilized remains of diatoms, a type of single celled algae. This fine filter media is considered to be more effective at filtering out microscopic particles of waste and debris than standard, continuous filtration methods such as wet/dry, canister or power filters.