How to Adjust pH Level of Water

The pH of a liquid refers to whether it is acidic, alkaline or neutral. A pH measurement of 7 is neutral; anything lower is acidic and anything higher is alkaline. Most freshwater fish do best in an environment with a pH between 6.6 and 7.8. Fortunately, most tap water falls in that range. The problem most people have with their aquarium is maintaining a constant pH balance, rather than achieving an optimal reading. Effectively adjusting and maintaining your pH level is important for keeping your fish healthy.

Things You'll Need

  • pH gauge
  • pH test kit
  • Clean container
  • Reverse osmosis unit
  • Commercial pH decreaser
  • Commercial alkaline buffer
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Instructions

    • 1

      Test the pH in your tap water and aquarium water. Gauges and pH test kits are available at any pet store that sells freshwater fish. Run your tap water into a clean container and perform the pH test according to the manufacturer's instructions. If the reading for your tap water is acidic, move on to Step 3; if it is alkaline, move on to Step 2.

    • 2

      Run the alkaline tap water through a reverse osmosis unit to remove some of the minerals and allow the commercial pH adjuster to be more effective. Add a pH decreaser to the water and test your tap water again until it is within a pH reading of 6.6 to 7.8. Try to get a reading slightly higher than your aquarium water, because the water in your aquarium naturally tends toward the acidic end over time. Move on to Step 4.

    • 3

      Add minerals to your acidic tap water with a commercial alkaline buffer and test your tap water again until it reaches the desired range. Aim for a reading slightly above the reading in your aquarium water, since fish waste naturally tends to push the reading lower.

    • 4

      Drain the recommended amount of water from your aquarium as you normally would to change the water. Usually you replace 10% once a week or 15% to 20% every other week. Add the treated tap water to the siphoned aquarium. Test the water in the aquarium again to ensure the level falls in the best pH range.