PH levels


Well-known member
Oct 8, 2009
Maybe someone can give me some insight into PH does the water temperature affect the pools PH level? I read somewhere that once the water starts to warm up the PH level will go down? Is that true?


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
In a typical swimming pool the PH will go up as the water get colder, and go down as the water gets warmer. This effect isn't all that large. During swimming season the change in PH with temperature isn't normally noticeable, since the water temperature usually doesn't change all that much. But there can be a noticeable difference between swim season and the middle of the winter.

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
San Rafael, CA USA
For example, going from 85F to 45F usually results in the pH rising from around 7.5 to between 7.7 and 7.8, for example, and then falls back down when the water warms up. Of course, there can be carbon dioxide outgassing or other factors in the interim causing a pH rise that somewhat obscures the drop back down.

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