My pool was opened on Tuesday. The pH has been low, which is not surprising because I had to put a lot of tap water in because the water level was low due to a leak when it was opened.
I've put in half a box of borax and about 3 lbs of soda ash. The pH is up to 7.2, so I'm thinking it must have been a lot lower than the 7 it tested at at opening.
I just tested again (at 7.2) and left the test on the counter while I went outside and put in more soda ash. When I came back the color had changed and showed about 7.8. Is that to be expected? Is 7.2 the right number?
BTW, I have some very old test strips and used one to check the pH after the color change incident. It said 7.