I monitored the button today, opens little. maybe from the shock of FW. But think its surviving. Hope for the best.
As for the cyano, I brush some off with my finger while washing. So most of them gone liao. All these happens quite fast, in matter of days.
Mine is only a 2 feet tank, before I put the buttons in, my tank was full of cyano, but finally remove them by changing filter to cannister with bio agents. Not much corals left liao, so worth a risk to salvage whatever in there.