How to Control Marine Red Slime Algae

The red slime algae that develops in some saltwater tanks is not really algae. It is actually a form of bacteria called cyanobacteria. It thrives on the nutrients in the water, including leftover fish food and their waste products. It also needs red spectrum light and nitrates. Once this bacteria is in your tank, it may be difficult to get rid of, since you can't stop feeding your fish or stop them from producing waste. There are, however, measures you can take to help control the environment in the tank to prevent the growth of this unwelcome presence in your tank.

Things You'll Need

  • Tank filtration system
  • Skimmer
  • Commercial aquarium cleaning product
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Instructions

    • 1

      Keep conditions in the tank as clean as possible. Wash your hands before handling anything that goes into the tank or before putting your hands in the water. Do not put in more food than the fish will eat to reduce excess buildup on the bottom of the tank. Keep the tank itself clean by removing waste products from the bottom and cleaning any decorative items, rocks or coral where the bacteria may grow.

    • 2

      Install a good filtration system to keep the water aerated and moving, both of which help keep nitrates levels low. Use a surface skimmer frequently to remove any materials on the surface stirred up by the filtration system.

    • 3

      Change the tank light frequently, since some lights emit more red spectrum light as they weaken over time. Keeping new strong lights in the tank helps prevent excessive red spectrum light, one of the cyanobacteria's source of nutrients.

    • 4

      Use a commercial product designed specifically for red slime algae removal and control. These are available at pet stores and aquarium supply retailers.