coral dying

My tank has been having a creeping issue. About a two months ago my croc island scoly, after doing amazing for 6 months slowly withered on one side and died. Weeks later my one of my Acan colonies started to not fully open. This was a colony that had been in the tank a year plus. I waited to...

Anybody have advice for slowing dying off SPS (especially Acropora)? Over the last few months, numerous species of SPS that were thriving and growing/spreading quite nicely for a long time began to slowly all die back :-( The fish and all other coral species, urchins, anemones, etc. are all...