By AquaMart Staff

How to Manage Hair Algae in your Reef Aquarium

Hair algae (filamentous green algae) can quickly become a problem in reef aquariums, covering rocks, corals, and equipment. Here’s how to deal with it effectively:

  1. Manual Removal
  • Use Tweezers or a Toothbrush:
    • Scrub hair algae off rocks, equipment, and surfaces.
    • Be gentle around corals to avoid damage.
  • Siphon During Removal:
    • Use a siphon to capture loose algae fragments to prevent it from spreading.
  • Remove Infected Equipment:
    • Clean algae-covered equipment and rocks in a bucket with saltwater outside the tank.
  1. Reduce Nutrients (Nitrate & Phosphate)

Excess nutrients are the primary cause of algae growth. Aim to keep:

  • Nitrate: Below 5 ppm
  • Phosphate: Around 0.03 ppm

Ways to Reduce Nutrients:

  • Protein Skimmer: Removes dissolved organics before they break down.
  • GFO (Granular Ferric Oxide): Absorbs phosphate from the water column.
  • Carbon Dosing (e.g., Vodka, Vinegar, BioPellets): Promotes bacterial growth to consume nitrate and phosphate.
  • Refugium: Grow macroalgae (like Chaetomorpha) to outcompete hair algae for nutrients.
  • Reduce Feeding: Feed small, controlled portions and rinse frozen foods to reduce nutrient input.
  1. Improve Flow & Lighting
  • Increase Water Flow:
    • Hair algae thrive in low-flow areas, so add powerheads or adjust water flow to prevent buildup.
  • Adjust Lighting:
    • Reduce light intensity or photoperiod to limit algae growth.
    • Replace Old Bulbs or LEDs: Lighting that has shifted in spectrum can encourage nuisance algae.
  1. Add Algae-Eating Livestock (Clean-Up Crew)

A clean-up crew can help control algae naturally, though they may not eliminate it completely.

  • Fish:
    • Lawnmower Blenny
    • Foxface Rabbitfish
    • Kole Tang or Yellow Tang
  • Snails:
    • Turbo Snails
    • Astrea Snails
    • Trochus Snails
  • Crabs:
    • Emerald Crabs (though not always reliable)
  1. Chemical Treatments (Use with Caution)
  • Algaecides (e.g., API AlgaeFix Marine):
    • These products can help control algae but should only be used as a last resort.
    • Monitor your tank carefully, as rapid algae die-off can cause ammonia spikes.
    • Run activated carbon and perform water changes after using chemicals to remove toxins.
  1. Maintain a Healthy, Balanced Aquarium
  • Regular Water Changes:
    • Perform 10–20% water changes weekly to export excess nutrients.
  • Test Water Parameters Regularly:
    • Check nitrate and phosphate levels to stay ahead of algae issues.
  • Monitor Source Water:
    • Use RO/DI water for top-offs and water changes to avoid introducing nutrients.
  1. Use a UV Sterilizer (Optional)
  • A UV sterilizer can help control algae spores and other free-floating organisms, reducing the chance of algae outbreaks.
  1. Prevent Future Outbreaks
  • Quarantine New Additions: Hair algae can hitchhike on new corals, rocks, and inverts.
  • Clean Equipment and Tools: Rinse tools in fresh water after use to avoid introducing algae spores.
  • Maintain Good Husbandry: Stay consistent with feeding, water changes, and nutrient control.

By combining manual removal, nutrient control, increased flow, and a clean-up crew, you can eliminate hair algae and prevent it from returning. Patience and consistency are key to long-term success!

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