By AquaMart Staff

How to Control Bryopsis in your Reef Aquarium

Bryopsis is a stubborn macroalgae that can quickly overtake reef aquariums, smothering corals and outcompeting other beneficial organisms. Here’s a step-by-step guide to eliminating bryopsis:

  1. Manual Removal
  • Use Tweezers or a Scrubbing Brush:
    • Gently pluck bryopsis from rocks and surfaces.
    • Be careful not to release fragments into the water, as this can spread the algae.
  • Siphon while Removing:
    • Use a siphon hose during manual removal to capture loose fragments.
  1. Raise Magnesium Levels with Fluconazole (Preferred Method)
  • Fluconazole is very effective in killing bryopsis.
    Steps:
    1. Remove as much bryopsis as possible manually.
    2. Turn off the protein skimmer and remove any activated carbon or chemical media.
    3. Dose Fluconazole at 20 mg per gallon of tank water.
    4. Let the tank run for 14–21 days without water changes.
      • Bryopsis will start to turn white and disintegrate within the first week.
    5. After 14–21 days, perform a large water change (20–30%) and replace your carbon or other chemical media.
  • Caution:
    • Monitor tank parameters closely during treatment.
    • Fluconazole does not harm corals, fish, or most invertebrates but may affect beneficial algae (like Chaetomorpha in refugiums).
  1. Increase Magnesium Levels
  • Raising magnesium levels to 1600-1800 ppm has been reported to kill bryopsis.
    • Steps:
      1. Slowly increase magnesium by 100 ppm per day until you reach 1600-1800 ppm.
      2. Monitor alkalinity and calcium to avoid imbalances.
      3. Maintain elevated magnesium for 2–3 weeks, or until the bryopsis turns white and disintegrates.
    • Note: Not all magnesium supplements are equally effective.
  1. Control Nutrients (Nitrate & Phosphate)

Bryopsis thrives in nutrient-rich environments, so reducing nitrates and phosphates is essential:

  • Nitrate: Keep levels under 5 ppm.
  • Phosphate: Maintain levels around 0.03 ppm.

Methods to Control Nutrients:

  • Use a Protein Skimmer to remove organic waste.
  • GFO (Granular Ferric Oxide): Absorbs phosphates effectively.
  • Carbon Dosing (Vinegar, Vodka, or BioPellets): Promotes bacteria that reduce nitrate and phosphate levels.
  • Refugium with Macroalgae (e.g., Chaetomorpha): Competes with bryopsis for nutrients.
  1. Add Algae-Eating Livestock

Although bryopsis is tough and not a preferred food, some creatures may nibble on it:

  • Sea Hares
  • Turbo Snails
  • Rabbitfish (e.g., Foxface)
  • Emerald Crabs (some will eat young bryopsis).
  1. Improve Water Flow and Lighting
  • Increase Flow: Bryopsis tends to grow in low-flow areas, so adding or adjusting powerheads can discourage its spread.
  • Check Lighting Spectrum: Old or improperly balanced lights may encourage algae growth. Ensure your lights are appropriate for corals but not overly intense for algae growth.
  1. Prevent Future Outbreaks
  • Quarantine New Corals, Rock, and Inverts: Bryopsis can hitchhike into your tank on frags or live rock.
  • Regular Water Changes: Maintain consistent water quality.
  • Monitor Nutrients: Test nitrate and phosphate weekly to stay ahead of problems.

By using a combination of manual removal, chemical treatments (like fluconazole), and nutrient control, you can eliminate bryopsis from your reef tank and prevent future outbreaks.

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