How to Cultivate Micro Algae

Microalgae, or phytoplankton, create most of the world's oxygen, support the ocean food chains and are a useful crop for food, animal feed and ethanol production. However, they also contribute to ocean dead zones. An aquarium owner might wish to cultivate microalgae on a small scale to feed aquarium fish fry and filter-feeding invertebrates. For example, if you breed clownfish, you need microalgae to feed the tiny invertebrates the clownfish fry eat.

Things You'll Need

  • Bucket
  • Aquarium salt mix
  • Transparent plastic bottles, 1- to 5-gallon
  • Air pumps
  • Fluorescent light source
  • Plastic tubing
  • Tubing connector
  • Algae fertilizer
  • Algae starter culture
  • Plastic container
  • Pipette
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Instructions

    • 1

      Draw enough tap water into one or more buckets to fill the bottles. Let the water set for at least 24 hours to allow it to dechlorinate.

    • 2

      Stir a salt mix into the water to bring the salinity to an appropriate salinity for the algae species you plan to cultivate and the organisms they are to be fed to -- in most cases seawater strength.

    • 3

      Fill one or more large plastic bottles with the water. Fill each bottle to within three to four inches from the top.

    • 4

      Illuminate the bottles with a fluorescent light for 12 hours a day or place them where good natural daylight is available. Place the bottles where they will remain at a moderate room temperature. Phytoplankton are not particularly temperature-sensitive but should not be subjected to extreme hot or cold.

    • 5

      Run plastic tubing from the air pump to the bottle, or to a connector to which you also will attach additional tubes if using more than one bottle. Normally one air pump is sufficient for two or three bottles. Use more pumps, if necessary.

    • 6

      Add algae fertilizer to the water, according to directions.

    • 7

      Add the algae starter culture and leave for two to three weeks to allow the algae to multiply. The culture has matured when the water is very green. You can check the density of algae under a microscope, if you are curious.

    • 8

      Transfer small amounts of the algae culture to your aquarium as required to feed your animals. Pour algae water from the bottle into a plastic container and pour slowly into the tank, or use a pipette if you require only a small portion.