How to Increase the pH in Water

In most saltwater and freshwater aquariums, pH should be neutral, or around 7. Low pH means the water is too acidic and can indicate that there is not enough oxygen in the water. Most aquariums maintain pH-neutral environments on their own using filtration systems, gravel, and the biological filtration system created by the fish and plants. Sometimes low pH in the water or other factors can cause water to become too acidic and kill the fish.

Things You'll Need

  • Litmus strips with color chart
  • Aeration filter
  • Aquarium plants
  • Crushed coral gravel
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Instructions

    • 1

      Find out why your fish are looking unhealthy before attempting to adjust your tank's pH. Low pH and poor oxygen levels can make fish look ill, but other factors can contribute to this, such as the fish not having enough of the same species to school with, not having enough places to hide, or feeding problems like too much or too little food, or the wrong type of food. Too many fish in the tank can also negatively affect the environment.

    • 2

      Test the water's pH with litmus strips. Dip one end of a strip into the water and check it against the color chart to approximate the water's pH. Test the water every day for two weeks between water changes and take an average. Small fluctuations in pH are normal. In general pH between 6.5 and 7.5 is acceptable for most fish. Some fish have special requirements, so find this out before buying new fish.

    • 3

      Check the filter and aeration if pH levels are low. Low pH means oxygen isn't being absorbed into the water properly. The filter should create air bubbles on the surface of the tank, which shows oxygen is coming into the water. Make sure the tank isn't too tightly covered so the surface water can mix with oxygen in the air.

    • 4

      Put some live plants in your aquarium. The plants will act as natural filters as well as release oxygen and absorb carbon dioxide in the water. High levels of carbon dioxide contribute to lowered pH. Plants will also keep the fish happier because it will make the aquarium mimic their natural environment and give them places to hide. After adding the plants, test the water's pH as in Step 2 for another two weeks before making additional changes.

    • 5

      Add a layer of crushed coral gravel underneath the aquarium gravel. The gravel will break down slowly in the tank releasing minerals that will raise pH. This won't make an immediate change, but is an effective pH buffer over time. Test the water's pH as in Step 2 for another two weeks.