Filter media
Filter media
Media choice matters less than media order and media maintenance. Coarse to fine, with biological media downstream of the mechanical stage, and never replace everything at once.
Short answer
The material inside the filter. Coarse sponge traps large debris, fine floss polishes, ceramic or plastic bio-media houses bacteria, and chemical media targets specific dissolved substances.
What it does
- Mechanical trapping
- Biological surface area
- Chemical adsorption where used
Strengths and where it fits
Strengths
- Fully customisable
- Cheap alternatives — cut-to-size pond sponge, bulk floss — work as well as branded ones
Good fit for
- Every filter
Limitations and where it is the wrong choice
Limitations
- Marketing claims about surface area are rarely comparable between products
- Chemical media is exhausted within weeks and then does nothing useful
- Disposable cartridges combine mechanical and biological function so that discarding one discards both
Poor fit for
Sizing
- Order flow through the filter coarse first, fine last, biological media after the mechanical stage.
- Replace no more than a third of the biological media at a time, and leave at least a month between replacements.
- Rinse in removed tank water, never under a tap.