How to Change a Fish Tank From Salt Water to Fresh Water

It is reasonably simple to convert a saltwater tank to a freshwater tank. However, you must be very thorough when you are cleaning out the tank and making the conversion, or you will promptly kill all your freshwater fish when you install them in their new home. The key to success is to extensively treat everything to remove every trace of the previous marine environment before you even think about moving any fish into the area.

Things You'll Need

  • Vinegar
  • Plastic scrubbing pads
  • Bleach
  • Plastic tubs
  • Distilled water
  • New filter
  • pH testing strips
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Instructions

    • 1

      Empty the aquarium completely. Dispose of all the water and remove plants, gravel, filtering equipment and rocks.

    • 2

      Wipe down the inside of the aquarium. Use cleaning rags saturated in vinegar to remove all traces of algae from the sides and bottom of the aquarium.

    • 3

      Scrub off all salt residue using scratchy plastic scrubbing pads. Use more vinegar and warm water to remove all traces of salt buildup.

    • 4

      Wipe down the sides of the aquarium again using a new cleaning rag and vinegar. This is very important since you cannot have any traces of salt in the new freshwater environment.

    • 5

      Rinse the gravel, rocks and any artificial plants in a bleach and water solution. Use 1 gallon of water and 2 cups of bleach. Pour the water through the gravel while you stir the gravel around. Then you can place the gravel in one tub filled with the bleach and water solution, while you leave the rocks and the plants in another. You might want to scrub down the rocks and plants as well while they are in the bleach bath. Allow the gravel and other paraphernalia to remain in the bleach bath for about a week.

    • 6

      Rinse down your gravel and plants with distilled water. Rinse and wipe down your gravel and plants one more time to make sure that they are free of all residue.

    • 7

      Fill the aquarium with new water. It will need to be dechlorinated for your freshwater fish. You should install a new filter as well that does not include a protein skimmer, since these are not necessary for saltwater tanks. You can replace the gravel and plants in the aquarium.

    • 8

      Monitor the pH of your tank. Do not move in any fish until it remains steady between 6.6 and 7.2 at the outer ends of the spectrum.