
organic sediment at bottom of an aquarium
Found on
http://phrontistery.info/m.html

Solid waste materials such as plant parts, fish excrement and leftover food in various stages of decomposition. Aquatic 'compost' which benefits plants, but in an unplanted, poorly maintained system may result in a buildup of humic acids which will decrease pH over time leading to Old Tank Syndrome.
Found on
http://www.aquahobby.com/articles/e_glossary.php
No exact match found.