How to Reconstitute RO Water for Discus

Discus fish are not difficult to keep, but they do require specific water qualities to thrive. Soft, slightly acidic water with a pH between 5 and 6.5 is one of the most difficult conditions to replicate in the home aquarium, as most tap water tends to have a much higher pH. Reverse osmosis (or RO) water is totally pure, low in pH and can be used to great success, but only after important trace minerals are added back. This process is most easily accomplished by mixing tap water until proper conditions are met.

Things You'll Need

  • 5 gallon bucket
  • Measuring cup
  • Water test kit
  • Holding containers
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Instructions

  1. Reconstituting RO Water for Discus

    • 1

      Determine the proper RO/tap water ratio before you add the water directly to your tank. Pour 1 gallon of RO water into the 5 gallon bucket. Add tap water to the RO water 1 cup at a time, testing the pH every few cups until the desired level is reached. To ascertain the percentage of tap water to add to the tank, divide the number of cups you added by 16 (the total number of cups in a gallon). For instance, if 8 cups of tap water to the gallon yields the correct water chemistry, your tank will be 50 percent RO water and 50 percent tap (8 divided by 16).

    • 2

      Filter any tap water that will be used before mixing it into the tank. This can be done by adding commercial water treatment products, "aging" the water for 24 hours in open-topped containers or filtering through an activated carbon filter. The best filtration process involves all three steps. Using unfiltered tap water can nullify any benefits of RO water by introducing harmful chemicals and dissolved metals back into the tank.

    • 3

      Add your RO water to the tank based on the percentage from Step 1. Slowly mix in your filtered tap water until the tank is full. Make a final round of water quality tests and adjust as needed.