How to Lower PH in Fresh Water

For various reasons, fish owners occasionally need to lower the pH of the fresh water in their aquariums. While pH can be easily raised by pouring additives into an aquarium, these additives will not work for more than a day when it comes to lowering pH. This is because the buffering system of the tank will regulate out the additives and reset the tank's pH to its original level. The buffering ions of the tank must be taken out in order to successfully lower the pH, and the only real way to do this is to purchase a tap water purifier that is specifically designed for usage in fish tanks.

Things You'll Need

  • Tap water purifier
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Instructions

    • 1

      Purchase a tap water purifier from an aquatic or pet store. Ask a store representative to be sure the purifier you buy is meant for aquarium use.

    • 2

      Set the purifier to the pH you want for your water.

    • 3

      Attach the purifier to your aquarium filter and activate it. The pH of the water should lower to the designated pH completely in one to two days, once all the buffering ions have been filtered out of the tank.