How to Make a Salt Water Solution for Aquariums

Aquariums come in fresh or salt water varieties. Having the right kind of water in your aquarium is critical to the survival of your fish. When it's time to fill or change the water in a salt water aquarium, you can purchase premixed salt water solutions or marine salt mixes that you prepare yourself. Never use table salt or tap water in a salt water aquarium solution, as they both contain impurities and metals that may be harmful to your fish.

Things You'll Need

  • Distilled or reverse osmosis water
  • Marine salt mix
  • Large clean plastic trash can
  • Hydrometer
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Instructions

    • 1

      Acquire enough distilled or reverse osmosis water to fill your new salt water aquarium. If you're just doing a water change, you will need about 20 percent of your aquarium's total capacity.

    • 2

      Mix most of the marine salt mix and the distilled water together in a large clean plastic trash can.

    • 3

      Test the solution you've created with the hydrometer. You want to reach a reading of between 1.020 and 1.025 specific gravity. Too much marine salt mix means too high a reading; not enough makes the reading too low.

    • 4

      Add more salt mix--or more distilled water--until the hydrometer reading comes up between 1.020 and 1.025.

    • 5

      Let the water settle and siphon off any white residue at the bottom of the trash can.

    • 6

      Use the hydrometer to check the specific gravity again and ensure it is still in the desired range. Adjust as necessary.

    • 7

      Fill the aquarium with your salt water solution.