Every reef tank goes through algae phases. The good news: each type has a known cause and a known fix. Here is how to identify what you are dealing with and the protocol that actually works.
Diatoms (brown dust)
Normal in new tanks. Lasts 2–6 weeks as silicates from new sand and rock are consumed. No action required — cleanup crew handles it.
Cyanobacteria (red slime)
Caused by stagnant flow and nutrient imbalance. Increase flow, blackout 3 days, dose ChemiClean as last resort.
Green hair algae (GHA)
Phosphate driven. Manually remove, run GFO, increase nutrient export via skimming and water changes.
Bryopsis
Tough, feathery green. Use Fluconazole treatment over 14 days — coral safe.
Dinoflagellates
Snotty brown strings with bubbles. Raise nutrients, dose live phytoplankton, UV sterilize.
Every new coral is a potential vector for Aiptasia eggs, flatworms, red bugs, and montipora-eating nudibranchs. Dipping is non-negotiable.Bayer AdvancedActive ingredient imidacloprid.…
Both methods remove phosphate effectively. They suit different tank sizes and different operator personalities.GFO (granular ferric oxide)Passive, predictable, slow. Set in a…
Reef-keepers’ notes
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