How to Remove Nitrates From Freshwater Aquariums

The nitrogen cycle of a freshwater aquarium involves converting fish waste into ammonia and nitrates. In an ideal freshwater environment, a nitrate test kit would show a nitrate level of no more than 20 parts per million. Levels that read higher than this could cause excess stress to your fish, which could result in disease or death. To date, there are no additives on the market that claim to lower the nitrate levels in aquariums. The only way to truly remove them without damaging your aquarium's delicate ecosystem is through a partial water change and by adding live plants.

Things You'll Need

  • Aquarium nitrate test kit
  • Siphon
  • Large waterproof container
  • Distilled water
  • Live freshwater plants
Show More

Instructions

    • 1

      Test the water in your aquarium with a freshwater test kit to determine the nitrate level in your tank. A nitrate level of 20 parts per million or higher is an indication that the levels are unsafe for your fish.

    • 2

      Remove 20 to 50 percent of your aquarium's water into a large waterproof container. Filter out any rocks or other debris you do not want down your drain and then discard the old water.

    • 3

      Refill your tank with distilled water. You can also use tap water that has been treated with dechlorination tablets. For tropical aquariums, heat the water prior to adding it to your aquarium to prevent shock.

    • 4

      Add live plants to your aquarium to help prevent future spikes in nitrate level.

    • 5

      Test your aquarium weekly, and continue to do partial water changes until a stable level of nitrates is detected.