How to Get Brown Algae Out of an Aquarium

Algae spores lie dormant in most aquariums, and the introduction of excessive fish or plant waste provides the necessary nutrients spores need to multiply, forming a residue on decorations, plants and aquarium glass. Brown algae is activated by silicates found in tap water in conjunction with insufficient light. When these conditions occur, diatom organisms flourish and bloom into brown algae in your aquarium. This type of algae is one of the easiest varieties to eradicate with an algae magnet, toothbrush and a coarse cloth. Prevent a recurrence of brown algae by observing good tank maintenance, adequate lighting and feeding your fish correctly.

Things You'll Need

  • Coarse cloth
  • Algae magnet
  • Bucket
  • Toothbrush
  • Aquarium water test kit
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Instructions

    • 1

      Wipe brown fluffy deposits from your tank glass with a coarse cloth or algae magnet. Remove algae from affected tank decorations, scrub rocks and ornaments with a toothbrush. Diatoms come away from flat surfaces easily, but it can be difficult to clean textured rocks. Soak items in a bucket of hot water for about 30 minutes before rubbing away the brown algae under running water.

    • 2

      Soak substrate in hot water and agitate to remove as much algae as possible. Brown algae mainly affects low-lying tank items, such as gravel, in places where there is insufficient light. Once you correct lighting levels, any remaining brown algae in the gravel should die off naturally.

    • 3

      Check your water for signs of excessive ammonia, nitrate and nitrite with an aquarium test kit. In a new tank setup, fish waste and uneaten food can overload a new filter before a beneficial bacteria colony has a chance to grow. Toxic chemicals rise to dangerous levels, and algal blooms develop. Carry out a partial water change if ammonia, nitrate and nitrite are above normal levels indicated on the test kit's guidelines.

    • 4

      Do not overfeed your fish. Uneaten food decomposes, releasing the nutrients that algae spores need to grow. If you have an algae problem, feed your fish every other day until you start to see a difference in the amount of algae on your aquarium glass. Add some algae-eating fish to keep all types of algae under control. They are unlikely to consume an established outbreak, but algae-eating fish constantly graze on new growths before they can flourish, so use the fish as a preventative measure.

    • 5

      Increase the lighting levels in your aquarium to between 10 and 12 hours per day. Too much light encourages green algae, so adjust the number of daylight hours gradually over 3 or 4 days. If you see a green bloom replacing the brown algae on your aquarium glass, reduce the lighting by 30 minutes the following day.