Algae in My Marine Tank

Algae are living organisms common to marine environments. They are also common in saltwater aquariums, but can easily grow out of control, as the enclosed environment will supply a continuous supply of food. They feed on nutrients contained in fish feces and food, and multiply rapidly when given plenty of light. Algae can be encrusting or floating, and while they usually do not cause imminent danger to the inhabitants of the tank, their presence grants little aesthetic pleasure as they discolor the water, stain decorations and give the aquarium a generally dirty appearance. The main preventive measure is good tank housekeeping with regular changes of water, but if algae should invade the aquarium environment, a few steps can keep them from taking over.

Things You'll Need

  • Marine gravel or sand
  • Filtration material (socks, sponges, cartridges -- depending on your system)
  • Purified water
  • Salt mixture without phosphates
  • Reverse osmosis unit
  • Angelfish, snails, starfish, hermit crabs, blennies
  • Saltwater or reef plants
  • Light bulb for aquarium lighting system
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Instructions

    • 1

      Turn off the aquarium lights and screen the tank from direct sunlight. Algae thrive and multiply in bright and sunny environments. Your fish will cope well without illumination, but if you keep corals, it is advisable to place them in a different tank or container with a light source while you fight the algae.

    • 2

      Remove as much of the algae as you can with a net or by hand. Thoroughly clean tank decorations, pumps and filters. Take away the upper layer of your tank gravel or sand and either clean it thoroughly with purified water, or replace it with new supplies.

    • 3

      Open your filtration system, clean the inside and remove the filter material, including filter socks, sponges or cartridges which will be clogged up or encrusted by the algae. Replace with new materials.

    • 4

      Remove approximately 20 percent of the water and replace it with a solution containing purified water and a phosphate-free salt mixture. Algae thrive on phosphate and you should keep levels continuously low, or nonexistent. Consider installing a reverse osmosis unit in the tank which will deionize tap water and keep it low on phosphates. Reverse osmosis units in 2010 cost approximately $50, while replacement cartridges are charged at $21.

    • 5

      Introduce some new friends to your tank. Angelfish, snails, starfish, hermit crabs and blennies feed on all kinds of algae and will keep the tank environment balanced and pretty.

    • 6

      Increase the plant life in your tank. Reef plants require the same nutrients as algae and their continuous presence can prevent algae from growing out of proportion.

    • 7

      Change the bulbs in the tank lighting system and switch on the lights again after 3 to 4 days. Do not keep the lights on continuously, but turn them on and off in 12-hour cycles.

    • 8

      Continue to clean and replace the water once a week until the algae presence has been reduced to a minimum level.