Biological filter media gives beneficial bacteria a place to colonize and remove toxins produced by organic waste - the single most important process for the health of your aquarium. Choose biological filter media by the type of filter you are using, and how much surface area you need (if you have a heavy bio-load, maximize surface area). Denitrifying bacteria are aerobic; keep oxygen levels healthy with an air pump or aerating water pump.
When it's time to clean your media, don't remove it all at once - bacteria takes a while to get established and removing it leads to catastrophic spikes in ammonia and pH. If your filter isn't designed for partial media changes, pack multiple filter bags only rinse one at a time in aquarium water. Browse by brand, type, or scroll down for our complete selection!