Turf algae (Cladophora + filamentous greens)

Symptoms

• Thick green carpet on rocks
• Dark green tufts on filter intakes
• Fast spread (1-2 weeks)
• Dense filaments difficult to remove
• Smothers coral or low-light plants

Cause

Excess nitrate (>10 ppm) + phosphate (>0.1 ppm) + intense light. Common in tanks 6-18 months old as nutrients accumulate. Often introduced on hitchhiker rocks.

Treatment options

• Manual removal + scrape. Scrub with toothbrush + magnetic algae scraper. Siphon out detached filaments before they decompose. Repeat weekly.
• Reduce nutrients. Larger water changes (50% weekly), reduce feeding, add chaeto refugium (SW), add fast-growing stem plants (FW).
• Algae crew (SW). Tangs (yellow, sailfin, hippo), urchins, foxface, large turbo snails. Mexican turbo eats most varieties.
• Algae crew (FW). Amano shrimp, otocinclus, Siamese algae eater (true SAE), bristlenose pleco.
• Fluconazole nuke. For severe outbreaks: 20 mg/gal fluconazole works well on bryopsis + green hair algae. Reef-safe but kills macroalgae too.

Always treat in a separate quarantine or hospital tank.

Prevention

Maintain nitrate <5 ppm reef / <30 ppm FW. Phosphate <0.1 ppm reef. Limit photoperiod to 8-9 hours. Clean filter media regularly.

Fatality + outcome

Not fatal directly. Outcompetes coral/plants for light + nutrients; kills sensitive species over time.

Related

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