Just got done shocking my pool for about 3 days. I hadn't tested PH during this time because I read on this site that PH test is unreliable at high chlorine levels. With CYA=60, I was shocking in the FC=high 20s.
FC is now down to 10.5ppm and I tested PH expecting it to be high since I shocked with liquid chlorine.
However, PH has gone from 7.6 down to 7.0-7.2 during shocking.
Is this possible? I've run the test several times to be sure.
According to pool calculator, about 3lbs of Borax should do it, but I was expecting to have to add acid.
I did use a little chlorine neutralizer to get FC down before a play date. Not sure if that could drop the PH.