I asked Waterbear to look at this post about the rising ph and alkalinity, since he is great with pool chemistry :


Marie, I went through the thread , posted, and hopefully explained a few things that are going on. The big red flag for me was '3 month algaecide'. All the ones that I have seen like this are copper! Might explain part of the green water, not to mention the iron! This is YOUR area of expertese so the ball is in your court!

As far as the alk and pH...2 possible reasons.
1. It can take a LOT of acid to overcome the high ALK, which is a buffer that keeps the pH from changing, before you start to see the pH move at all.
2 High chlorine levels will interfere with both ALK and pH tests. pH tests will read 8.2 even thoough the pH is much lower because the phenol red has been converted to chlorophenol red which is used to test the pH range of 4.6 to 6.8 and gives the same color at 6.8 that phenol red gives at 8.2! All you really know is that the pH is somehwhere above 6.6![/QUOTE]