Asked By: Larry from St. Paul, MN
A: The ideal pH level for koi ponds is between 6.5 and 8.5. Check the pH of pond water using a wide-range pH test kit. Before making any changes, test the water three times a day over five days. If your readings consistently falls outside this range, add The Pond Guy pH Stabilizers to raise or lower pond pH naturally and bring it into balance.
Ensure you add pH stabilizers slowly and measure levels one hour after each application to check progress. Make adjustments in 0.5 pH increments to avoid shocking your fish, which can leave them vulnerable to illness.
Mississippi State University recommends altering pH levels in late fall or winter so the water has time to reach equilibrium before fish grow and increase activity in spring and summer. However, you should test water regularly and correct severe pH imbalances (less than 6.0 or greater than 9.0) whenever issues are detected.
Learn More About Perfecting Water Parameters
If you are struggling to maintain proper pH levels or battling other water quality issues, we can help! Contact us online or call 866-POND-HELP to speak with an experienced pond expert.
Continue reading about garden pond water clarity in the following helpful guides:
Pond Carbonate Hardness & Alkalinity
Beneficial Bacteria for Balanced Ponds
The Importance of Pond Water Changes
Last Updated: March, 25, 2025