PH different when pump on vs. Off

[Oakleyc]

I tested my ph this morning before pump was on after sitting for the night and it read 7.0. Tested after got home from work and it read 7.7. Anyone know why it would read differently and which reading is correct?

 

[ajw22]

How new is your pool?

Test your PH tomorrow and report.

 

[JamesW]

If it rained or fill water was added, the top water can be different.

 

[woodyp]

We recommend taking a sample at least elbow deep 30 minutes after starting circulation for consistency and proper mixing.