Water Temperature Effect on Testing

Bill in SoCal

LifeTime Supporter
Jun 9, 2014
Hacienda Heights, California
Just wondering if water temperature would have any appreciable effect on testing results? Just started doing my own pool maintenance and care late this spring. Over the summer my water temperature was typically 80+ degrees fahrenheit. Now the water temp is regularly in 55-65 degree range. I live in southern California. Thanks in advance for any info that may provide......


LifeTime Supporter
Platinum Supporter
TFP Expert
May 7, 2007
Silver Spring, MD
Water temperatures don't really matter to any of the tests except the CYA test. There are situations where cold water can cause the CYA test to read low, though that doesn't always happen. Cold water makes it more important to do the chlorine and PH tests soon after taking the water sample, though that is always important regardless.


Well-known member
Nov 29, 2011
Magnolia Texas
On my salt water pool my ppm of salt seems to increase as the temperature drops. I read the salt ppm from my panel. it went from 3100 ppm to 3300 ppm in the last couple of weeks as the water temp has dropped from the low 70's to the mid 50's.
Sep 15, 2014
Dawson MN
That's interesting to know because we close down for the summer, but still test water periodically to keep the water balanced. When we are open our water temp is 85 degrees and when we are closed we drop it to 55 degrees. Thanks I have learned that when at the temp of 55 degrees I need to test that water for chlorine and the ph immediately after getting the sample. This forum is awesome
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