How to Lower Nitrates in a Freshwater Aquarium

When you set up an aquarium, you are essentially recreating a piece of nature in your own home. Recreating that natural environment faithfully can be a difficult proposition, since the confined space of the aquarium means that any contaminants in the water can quickly spiral out of control. No matter what the size of your aquarium, it is important to monitor the nitrate levels and reduce those levels before they have a chance to harm your fish.

Things You'll Need

  • Nitrate test kit
  • Bucket
  • Siphon
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Instructions

    • 1

      Test the nitrate level in your aquarium. You can buy nitrate test kits at your local pet store.

    • 2

      Replace the filter media in your power filter or corner filter. If the filter cartridge is blocked it cannot operate efficiently and that can cause the nitrate levels in your aquarium to spike.

    • 3

      Add an extra filter to your aquarium. Combining two different types of filtration can reduce the nitrate levels in your tank and make your fish healthier. For example, consider adding a power filter to an existing under-gravel or corner filter.

    • 4

      Use a siphon and gravel cleaner combination to remove 1/3 to 1/2 of the water in your tank. Discard that water and replace it with new water. Use spring water or water that has had its chlorine removed with a dechlorinator. You can buy dechlorinating chemicals at your local pet store.

    • 5

      Check the nitrate level in your aquarium 1 or 2 days after the water change. Reduce the number of fish in your tank if the nitrate levels are still spiking after you have changed the water.