Snails very unhappy

[nlreefguy]

This has hapened to me in the past, almost always associated with large or sudden shifts in pH and/or alkalinity. Yes, I've been dumb enough to let it happen more than once. I lost a lot of snails once when I started dosing kalk, in probably too large volumes at once and again when I added too much alaklinity to my top off water over a period of a couple of weeks (when I tested the alk it was 17).