I still say your problem is not the ph. My guess is high alk numbers. I think I would try dosing instead of the ca reactor for awhile and see if you see an improvement. There have been numerous posts here where people have problems like yours (low ph / burnt tips) using a reactor. I have considered a reactor do to the amount of alk/cal I'm dosing, but based on my research, I don't trust the reactor route. I know I'll take a beating for this post, but just my 2 cents worth.