How to Remove Aquarium Nitrite

A new aquarium or fish tank must complete the nitrogen cycle before the water is safe for fish. Good bacteria needs time to grow in a new setup, and a colony takes around three weeks to establish in the filter and gravel. Ammonia, nitrite and nitrate develop during this initial period, with the potential to harm or even kill your fish. Check your aquarium with a nitrite water test kit and replace a third of the water every three or four days as a preventative measure. If nitrite is already high, change half of the tank water.

Things You'll Need

  • Nitrite water test kit
  • Siphon
  • Fish net
  • Bucket
  • Floating thermometer
  • Water dechlorinator
  • Beneficial bacteria solution
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Instructions

    • 1

      Test your water for nitrite with an aquarium test kit, following the instructions on the bottle and compare your result to the color-coded chart in the kit. If the result is in the high color range and showing dangerous nitrite levels, change half of the aquarium water immediately.

    • 2

      Net out debris and siphon uneaten fish food and waste from the gravel to eliminate the cause of nitrite. Decaying plant matter and uneaten food causes ammonia, nitrate and nitrite levels to escalate during the nitrogen cycle because there is not enough healthy bacteria to decompose excess waste organic material. This is called new tank syndrome.

    • 3

      Carry out partial water changes twice a week to keep nitrite at a safe level. Remove a third of the aquarium water, putting aside a bucket of the old water to wash tank ornaments and gravel if necessary. Do not empty your aquarium because the nitrogen cycle starts over if you refill the whole tank with new water in one session.

    • 4

      Mix dechlorinator into a bucket of clean tap water, following the manufacturer's dosage requirements. Drop a floating thermometer in the water and add hot or cold water until it is the same temperature as your fish tank. Pour the new water into your aquarium.

    • 5

      Shorten the nitrogen cycle and balance nitrite with a beneficial bacteria solution. Use the solution at each water change and when adding new fish to boost your filter's efficiency. A strong bacterial colony creates a stable environment for your fish and maintains healthy aquarium water.