Mechanical media traps debris, biological media provides surfaces for nitrifying bacteria, and chemical media targets particular dissolved substances. Select each for a defined job.
Filter media gives water different kinds of treatment as it passes through a filter. Start with the problem you want to solve, then choose media that fits the filter’s space and flow.
| Media type | Main job | Common form |
|---|---|---|
| Mechanical | Traps suspended debris | Foam, sponge, floss or pads |
| Biological | Provides surface for nitrifying bacteria | Ceramic media, porous blocks or sponge |
| Chemical | Targets selected dissolved compounds | Activated carbon or specialty resins |
Mechanical media catches particles and is usually serviced when flow declines or debris accumulates. Biological media supports the bacteria involved in the nitrogen cycle. Keep it wet and follow the maker’s cleaning directions. Chemical media has a specific purpose and useful service life; it is not a substitute for mechanical or biological filtration.
Arrange media in the path recommended by the filter maker. Many systems put mechanical media before finer or specialized media to reduce debris reaching later stages, but layouts vary. Do not pack baskets so tightly that water bypasses media or the filter flow is restricted.
Replace chemical media according to its product instructions. Rinse or replace mechanical media as needed. Avoid replacing all biological material at once; use the filter and media instructions for maintenance intervals.
The filter types and sizing comparison helps choose hardware and flow. For a new aquarium, pair filtration with the nitrogen cycle guide and use tests to verify water conditions.
Sources
Common questions
What are the three types of filter media?
Mechanical media traps particles, biological media supports beneficial bacteria, and chemical media is used for specific dissolved substances.
Do I need activated carbon all the time?
Not every setup needs continuous carbon. Follow the media maker’s intended use and remove it when it is no longer appropriate.
How should I clean biological media?
Follow the filter and media maker’s directions; avoid replacing or cleaning all biological media at once.