Brown diatom algae
Brown dusty film on glass, plants and sand, common in new tanks.
A soft brown or golden film that wipes off easily, on the glass, substrate, decorations and plant leaves. It is most common in the first weeks of a new tank.
- Main cause
- A new tank: silicates and nutrients before plants and bacteria settle
- First fix
- Wipe the glass and rinse leaves; siphon it off the sand during a water change.
What causes it
- A new tank: silicates and nutrients before plants and bacteria settle
- Low light with spare nutrients
- Silicate-rich tap water or some sands
How to remove it today
- Wipe the glass and rinse leaves; siphon it off the sand during a water change.
- Otocinclus and nerite snails eat it, once the tank is cycled.
How to stop it coming back
- It usually fades on its own after the first month or two as the tank matures.
- Keep up water changes; plants that grow fast use up the nutrients it feeds on.
Fish and invertebrates that eat it
They keep it down once the cause is fixed; none of them clears a bloom on its own.