I had major problems when my water supply went from a crazy high hardness, something like 28 degree to 6 degree hardness.
The pH went from 8.7 with the hard water to 7.6 with the new water.
Pretty much a train wreck, I had no shrimp at the time, but no fish died.
The crypts melted, I knew that was going to happen, but came back, but all the stems died. Wow what a mess.