Stn and rtn wasn’t the cause… when you figure out what caused the stn,rtn most likely a alk spike that’s the issue.. it is not contagious, I promise you! There’s very old sps tanks that just get a ghost every once in while and everything else is just fine.. I’ve played that game many times over 20 years of keeping sps.. I just lost my asd rainbow Millie to stn while 60 other acros are flourishing and growing at record pace! Never changed a thing and the tank never skipped a beat. I’ve been scraping my montis lately to cause rtn cause they’re over running prime real estate and no issues at all!I disagree with that. It really depends on the cause. As I wrote I lost every sps in my tank due to rtn/stn. I suspect the rest would have been fine if I just removed the affected monti instead of blowing it clean.
Some parasites also seem to cause it.