Many thanks for the responses.

I had my readings verified by the local Leslie's. I tested my house water & the Ph is 7.3. I really didn't add that much water and my test kit goes down to 6.8. I've own pools for over 25 years and they all have been very steady & good in regard to Ph. Last year I replaced my original liner in my current pool after 17 years due to fading & my wife was "bored" with it.

I added another box of Borax & the Ph is back up to 7.6. I'll keep you posted. I still have no clues!

Regards, Ron