What Maintenance Do Under-Gravel Aquarium Filters Require?
With an under gravel filter you neither have to nor want to change your filter media. However, you will need to clean the gravel regularly. The easiest way to do this is by using a gravel vacuum and cleaning 1/4-1/3 of the gravel each time you do your monthly of semi monthly water change. This is necessary to prevent the gravel from “channeling,” where the debris collecting in the gravel blocks some passages and forces the water through channels, resulting in decreased water flow and reduced exposure to the bacteria that clean the water. Under gravel filters are generally the lowest maintenance filters and are the least expensive aquarium filters to operate.
