How to Extract Microalgae

Microalgae can quickly ruin a saltwater aquarium by smothering coral and taking up available nutrients and oxygen from the water. While the best way to remove algae is by removing its sources of nutrients (nitrate and phosphate in particular), sometimes the aquarist has to resort to physical methods of extraction. The procedure for doing so depends on the type of algae you have a problem with and your exact aquarium setup.

Things You'll Need

  • Turkey baster
  • Small powerhead
  • Bucket
  • Clean stiff brush
  • New toothbrush
  • Turbo snails
  • Emerald crabs
  • Blue-legged hermit crabs
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Instructions

    • 1

      Use a turkey baster to suck the algae off rocks, gravel and sand. This works best for loose algae such as cyanobacteria and brown algae (diatoms). Do not release the algae back into the aquarium water system, empty the baster into a bucket.

    • 2

      Use a powerhead (a type of small water pump) to blow the microalgae off the rocks. This is a quicker method of removing nuisance microalgae from rocks and other large, heavy objects. It will not work for sand because the jet of water will blow the sand into the water column as well as the microalgae. When using this method, make sure you have a fine mesh filter with granular activated carbon to remove the algae particles from the water. As an additional step, you can use an ultraviolet (UV) sterilizer to kill the algae cells when they are in the water.

    • 3

      Pull hair algae off the rocks with your fingers and remove it from the aquarium. You do not want to release the hair algae into the water column as it will release more nitrates and phosphates into the water system, causing more hair algae to grow.

    • 4

      Add animals that eat microalgae. In cases where the microalgae has taken over the aquarium, this step will likely not remove all the algae; however, an algae "clean up crew" is a great way to help keep algae in check. Some animals that are excellent microalgae eaters are turbo snails, emerald crabs and electric blue hermit crabs. Remember that these animals need some algae to live, so do not remove all traces of algae from the aquarium.