How to Stop Algae Blooming From Nitrates

Algae and aquariums go hand in hand. Algae are photosynthetic organisms that grow in both freshwater and saltwater. They become a problem when they interfere with the aesthetic appeal of your aquarium or the growth threatens to smother other organisms. When your water becomes green and cloudy, you have algae bloom. Various factors, or a combination factors, may result in rampant algae growth, including the nature and amount of light your aquarium receives and excessive levels of nutrient ions such as nitrates and phosphates. The only way to stop algae bloom is to control the conditions that foster its growth.

Things You'll Need

  • Nitrate test kit
  • Protein skimmer
  • pH and alkalinity test kit
  • Algae scrubber
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Instructions

    • 1

      Perform regular 25 percent water changes. Small changes on a more frequent basis are best to maintain an aquarium's stability. Test for nitrates on a weekly basis and change water when nitrate concentration rises above 25 mg per liter for fish only aquariums and 18 mg per liter for tanks with invertebrates. Test kits for nitrates measure either nitrate nitrogen or nitrate ion levels. Multiply a nitrate nitrogen level by 4.4 to convert it to a nitrate ion reading.

    • 2

      Install a protein skimmer in your aquarium. A protein skimmer removes dissolved organic matter and lowers the concentration of carbon dioxide of the water. Nitrate levels will be indirectly reduced, as dissolved organic matter is decomposed by bacteria into nitrate.

    • 3

      Check the pH and alkalinity of your aquarium water on a regular basis. If either of these readings is chronically low, carbon dioxide may be accumulating in the aquarium. This can happen when your pump is too small for your tank size or it has slowed down to poor maintenance or age. Perform a simple carbon dioxide test to confirm a carbon dioxide accumulation problem. Take a half-gallon sample of aquarium water and aerate it for 24 hours. Take pH readings of the sample and the tank at the same time. You have a carbon dioxide problem if the tank reading is over 0.2 pH units below the sample. In this circumstance, it is time to change your pump.

    • 4

      Cut back the number of hours of light your aquarium receives. When dealing with substantial algae bloom, turn off your tank light for a few days. After that, ensure that the lights are on for no more than eight hours a day. Ensure the tank is not getting direct sunlight, as even short periods of direct sunlight can be detrimental. Change your aquarium lighting at least once a year if using fluorescent or metal halide lighting and every four to six months if using VHO or HO lamps. With age, the intensity and spectral output of aquarium lamps change, sometimes triggering the growth of unwanted algae.

    • 5

      Clean your aquarium on a biweekly basis. Remove algae from tank panels on an as-needed basis with an algae scrubber. Do not remove all the algae, as some growth is beneficial to the environment of your tank. Vacuum gravel, where waste will accumulate and quickly degrade water quality. Rinse filter media on a monthly basis to prevent it from becoming clogged with waste.