Low pH and high Alk


Well-known member
May 5, 2020
I opened my pool for the year and its been running for 2 weeks. It's crystal clear and ran all my tests this weekend, but not sure what the right approach should be to correct the pH without adding more Alk. Any thoughts?

pH - 6.6
Alk - 90
FC - 6.0
CA - 30
CH - 75

This is an above ground vinyl pool so I am not super concerned about the high alk, but if I add soda ash or baking soda with all add both pH and Alk.


Gold Supporter
Jan 7, 2012
The Woodlands, TX
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
pH was measured with the TF100 Test Kit.
For the pH test in the TF-100, the bottom end of the scale is 6.8. How are you measuring 6.6?

How/why did the pH get that low?

With a TA of 90, your pH won't stay low for long. Aerate to speed up the pH rise.
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