So what I can gather, an imbalance happened in your system after treatment and some corals are not happy!!! Don’t do anything drastic and try to find there happy medium, get your PO4 down and NO3 up! It’s only my opinion and systems are hard to figure out over the internet, too many variables to consider!!! So please just take this advice with all of this in mind.
Did the byropsis at least go away???
And do you have a fuge with cheato or any macros in there before treatment ?
You might have something else that died with the treatment and is leaching PO4!!!
Look around in your sump and make sure that everything is good.
I hope that this helps you out some!!