Sounds like to me that your LFS is recieving or recieved some bad corals. Whats the LFS set-up like? Same lightinf? How long did the LFS tank the livestock you purchased? It's definitly not the mouse pad, but it could be something in the water. Copper test might be in order as store bought r/o is processed thru copper lines, not polym like ours. The quickness of death is what leads me to belive you recieved livestock on a lit fuse.