How to Reduce Ammonia Levels in an Aquarium

Ammonia is produced in the aquarium by the breakdown of organic matter and directly as a part of fish gill function. It is a natural part of the aquarium nitrogen cycle, but it is also highly toxic to fish. In a healthy, functioning aquarium, nitrosomonas bacteria colonize the filter and keep the water free of ammonia. However, in tanks that are newly set up, over stocked or inadequately filtered, ammonia levels can rise and threaten the tank inhabitants. Any detectable ammonia level is potentially damaging and so should be corrected with remedial water changes.

Things You'll Need

  • Bucket
  • All-in-one gravel cleaner and siphon
  • Jug
  • Aquarium water conditioner
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Instructions

    • 1

      Turn off all heaters, filters and air pumps, and leave heaters to cool for 20 minutes.

    • 2

      Insert the wider end of the siphon into the water and point the loose end into a bucket. Ensure the bucket is lower than the tank or the siphon may not work.

    • 3

      Start the siphon. Depending on design, this may require sucking on the loose end, pumping the siphon in the water or using a hand pump.

    • 4

      While the siphon is removing water from the aquarium, use the wider end to suck debris out of the gravel.

    • 5

      Stop the siphon once 75% of the water has been removed, and remove the siphon from the tank.

    • 6

      Empty the bucket down the drain or into your garden.

    • 7

      Refill the bucket with fresh water from your main supply.

    • 8

      Compare the temperature of the new water with the aquarium water using the back of your hand. Add hot or cold water as necessary to match the temperature.

    • 9

      Add water conditioner to the bucket of fresh water to ensure all chlorine, chloramine and heavy metals are removed. Follow the dosage instructions on the bottle. Mix well.

    • 10

      Using the jug, fill your aquarium with the fresh water. Pour slowly to ensure you do not disturb the substrate.

    • 11

      Correct any disturbed substrate, plants or ornaments.

    • 12

      Let the tank settle for 10 minutes to allow heater to reach the same temperature as the water.

    • 13

      Turn heaters, filters and air pumps back on.

    • 14

      Re-test your water after 12 hours. Repeat entire process if you have a detectable ammonia level.