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How to Make the PH in My Pond Higher

If you have koi or other ornamental fish in your garden pond, it is important to closely monitor the pH level of your pond water to maintain the health of your fish. If you discover that the pH level of your pond water is below 6, your pond may be too acidic to support healthy fish. Fortunately, you can raise the pH level of your pond yourself, using easy-to-find household ingredients to alkalize the pond water.


  1. Use a pH tester kit to obtain an accurate reading of the pond pH level. Most tester kits require collecting a water sample in a vial and then adding a drop of tester fluid to the vial. The resulting color can be compared to the tester-kit chart to determine the pH level. Most koi do best in water that is neutral or slightly basic, at a pH level of 7.0 to 8.5. A pH level below 6.0 may be dangerous for fish.
  2. Check the bottom of your pond for debris and decaying organic matter. If your pH level is between 6 and 7, you may be able to raise the pH level by simply removing debris from the bottom of the pond -- the debris may be providing food for pH-lowering bacteria. Use a net to scoop up any visible debris.
  3. Raise the pH level of your pond further by beginning daily water replacement. Test your tap water to ensure that it is at a pH of 7.0 or higher. Each day, remove 10 percent of the pond water with a bucket or rubber-hose siphon, and replace with fresh water. Continue testing the pH level of your pond daily.
  4. Boost a stubbornly low pH level by dissolving baking soda in a 5-gallon bucket, and poring the solution into your pond. Dissolve 16 oz. baking soda for every 500 gallons of pond water. Retest the pH level one hour after adding the baking soda solution.

Things You Will Need

  • pH tester kit (available at any pet store)
  • Pond net
  • Rubber hose
  • Baking soda
  • 5-gallon bucket

About the Author

Fred Samsa has been writing articles related to the arts, entertainment and home improvement since 2003. His work has appeared in numerous museum publications, including program content for the Philadelphia Museum of Art, and he was awarded a Presidential Fellowship in 2005. He holds a Master of Arts in art from Temple University and a Bachelor of Arts in philosophy from Brown University.