How to Fix a Nitrate Problem in a Saltwater Fish Tank

In order to maintain a healthy saltwater tank, you need to keep an eye on nitrate levels. You should get into the habit of testing your tank water's nitrate levels on a regular basis. Normally, a healthy saltwater tank has five to 10 ppm (parts per million) of nitrate. Any higher, and the nitrates will deplete all of the oxygen in the water, which can potentially kill your fish and plants.

Things You'll Need

  • Nitrate test kits
  • Siphon hose
  • Bucket (preferably two)
  • New prepared salt water
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Instructions

    • 1

      Check to see if the filter is working or if something has died that may explain the high nitrate reading. Fix the filter or remove any corpses if necessary and proceed to Step 2.

    • 2

      Do a partial water change to remove some of the high nitrate water. Take a bucket and siphon hose to the tank, suck on the hose to get the suction action going, and remove about one fifth to one quarter of the water.

    • 3

      Mix up replacement salt water in a second clean bucket or after the bucket of dirty water has been dumped and rinsed.

    • 4

      Lessen the amount of light getting to the tank. This could be turning off a room light or turning off the tanks lights entirely. Light encourages nitrates to grow.

    • 5

      Retest the nitrate level. If it is still far too high, do another partial water change.