How to Lower Nitrates Safely in a Goldfish Tank

While most species that live in aquariums depend on small levels of nitrates, nitrate levels that are too high can kill fish and other inhabitants of your aquarium. Nitrate occur as ammonia breaks down, and therefore may have a variety of sources. One major source is overfeeding, but items such as under gravel filters and filter pads can also contribute to nitrate levels. Your goal in lowering nitrate levels should be to reduce nitrate in the tank without shocking the fish by dramatically changing their environment in a short period of time.

Things You'll Need

  • Nitrate test kits
  • Bucket
  • Aquarium siphon
  • Clean water
  • Aquarium brush
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Instructions

    • 1

      Check your nitrate levels using a meter that any pet or aquarium store should have in stock. A minimum of 10 ppm of nitrate is a good minimum, and anything between 10 to 30 ppm should be OK. If you find significantly higher nitrate levels, then you must risk shocking the fish in your tank in order to remove the nitrates.

    • 2

      Clean the tank to remove any built-up food or fish waste, and dislodge anything that may continue to produce nitrates after you finish.

    • 3

      Prepare a clean amount of water equal to about one-third of your tank's total, and set it next to the tank. So if you have a 60 gallon tank, prepare 20 gallons of clean water and set it close to the aquarium.

    • 4

      Siphon off from your aquarium about half the total of the clean water and mix it with the clean water. So if you have a 60 gallon tank and you prepared 20 gallons of clean water, take out 10 gallons from the tank and mix the two. What you are doing here is diluting the dirty water with clean.

    • 5

      Pump the mixture into the tank until the tank is full and check the nitrate levels. If the nitrate levels are too high, siphon off another 10 gallons of aquarium water and mix it with the clean water. Then return the right amount back into the mixture.