Methods
Refugium or algae scrubber for nutrient control
Grow algae where you want it, under a light in the sump or on a screen, and harvest it to take nitrate and phosphate out of the tank. Cheap, natural and steady, with one catch for some dosing methods.
Last checked . How we check
- Cost
- Low
- Effort
- Low (harvest every few weeks)
- Suits
- Tanks with a sump; fish-heavy tanks
- Needs
- A sump chamber or scrubber and a light
How does it work?
A refugium is a lit sump chamber with macroalgae. Triton requires one as its first sump chamber, lit by T5 tubes, harvested every two to four weeks and kept under 32 C. It also shelters pods.
An algae turf scrubber grows algae on a screen with water running over it. Hobby sizing (typical, not peer reviewed) is about 6.5 square centimetres of screen per US gallon lit on both sides, lit 18 hours a day, cleaned every week; newer guidance sizes it by how much food you feed.
Does a refugium change my dosing?
Yes for some methods. Red Sea says its four-part Complete Reef Care is for systems without a refugium, because algae use alkalinity out of proportion to coral growth, and points refugium users to its seven-part programme.
How do I get started?
- Choose refugium or scrubber.
- Light it on a schedule, often opposite the display.
- Harvest every two to four weeks (refugium) or weekly (scrubber).
- Test nitrate and phosphate weekly so you do not strip them to zero.
What are the common mistakes?
- Never harvesting, so the algae dies back and releases what it took up.
- Running it with Red Sea's four-part set.
- Stripping nutrients to zero.
Where do sources disagree?
| Topic | What sources say | Our reading |
|---|---|---|
| Refugium with dosing |
| Pick the method first, then decide on a refugium. |
Sources
Figures from sources read as a search summary only are shown as typical figures: check them before you rely on them. Found a mistake? Tell us how to fix it.