I come home tonight, and most of my LPS, and SPS's are toast, and all of the zoa's are closed up. Everything tests out ok, PH is a little low, but it seems to always be low, the only thing I can think of is something got into my bucket before I did a water change yesterday.
PH - 8.1
KH - 9
Nitrate -
PH - 8.1
KH - 9
Nitrate -