Floyd, after that whole thread on kalk and vinegar, and learning the top end of how much vinegar you can use, I tried going from bare minimum (5ml per 5G) all the way up to 40ml per gallon. When I used 40ml per gallon I got 0 precipitates, but I found like you, the more vinegar I used the harder it was to maintain alk. Not sure why that is, but that was my experience. I have since went back to my super low vinegar and my pH and Alk are back to stable again. Just taking a wild guess, but BRS sells 2 "recipies" of 2 part, one that raises pH, one that lowers pH, I am wondering if by adding vinegar to kalk we are turning the kalk from recipe 1 into recipe 2 somehow.