ok, REALLY obsessing, LOL!
re-checked water from tap, got 7-7.2. rechecked tank, got same 8-8.2. did a 20% PWC, and now tank tests 7.5.
?????
why would the pH go UP all on it's own?
could be related to KH or DH? (neither of which I have any understanding of, nor can I test for them)
at least...