pool still covered, but actually tested all parameters today.
Since the previous post, I added 4 cups MA, over 3 days.
FC 10
CC 0
TA 40
CH 150
CYA 40-50
pH 7.4

my guess now is that there was still some Cl in the pool, and the additional just pushed it higher- teach me to assume!
The pH I guess was the result of circulating the water over several days...
Since the Cl is holding up, and no CC, I think I'm in good shape for removing the cover and starting the season!
Probably taking off cover this weekend, and then retest in a few days- hoping my temp holds, is at 68F now!