How to Raise the pH in Freshwater Fish Tanks

The pH of a solution refers to how acidic or alkaline it is. The pH scale ranges from 0 to 14, with 7 being neutral, 0 being the most acidic and 14 being the most alkaline. Most fish prefer water with a pH of around 6.4 to 7.8. You can change the pH of your freshwater aquarium, but take care to do so gradually because sudden changes can cause stress to your fish.

Things You'll Need

  • pH testing kit
  • Aquarium vacuum
  • Crushed coral bag
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Instructions

    • 1

      Test the current pH of your aquarium. Purchase a test kit from a fish store. Plan to test at least once per month to monitor the stability of your aquarium water's pH level.

    • 2

      Vacuum fish waste and uneaten food from the bottom of your aquarium. Aquarium debris that is left to dissolve into the water lowers the pH level. Purchase an aquarium vacuum from your local fish store, or make one yourself using some flexible plastic hose, a piece of straight plastic tube and a pail.

    • 3

      Perform regular partial water changes. Aquarium water that is left unchanged for extended periods slowly drops in pH. If you change 10 percent of your aquarium water once per week, you maintain the water quality without causing stress to fish in the way that complete water changes can.

    • 4

      Place a bag of crushed coral under the gravel at the bottom of the tank. This helps to keep the aquarium pH level from getting too low. You can also mix the crushed coral into your tank gravel without using a bag, but if the pH of your aquarium becomes too high, the coral is easier to remove if it is bagged.