Possibly, while you were in the hospital the levels might have gotten slightly out of wack without your on everything and maybe that caused weakening of corals in combination with the cyano. Then the chemi clean and lighting issues on top might have pushed the envelope a bit. .....patience and slow and steady changes.....This all started LONG before the lighting change Shawn. It started while I was in the hospital, sometime in late January. I started the lighting slow. I’ve had T5’s on the tank all along.
Hopefully, you will get things where you want them for both you and the tank