Just touching on all bases with the PH. Just because something was at a certain level doesnt mean that it is still at that level. Anyhow, if a coral is weakened for some reason it may stress easier than surrounding corals. Yes, I suppose vomiting is an appropriate term. I see this with my anemones, trachy's, welso's, plates, and acans/acantho's. Sometimes they expel their insides to clean themselves out but then they usually return to normal. How is it looking today? You can try re-dipping in revive or coralx but if it has been in the same spot for 7-9 months and is just now showing stress while other corals around it are looking healthy, then I can only guess that it wasn't totally healthy from the start. You would have no idea either and it sounds like you took the appropriate steps when introducing it to your tank. Sometimes a coral will look great when you first put it in the tank and for no explainable reason it just dies. I know many are seeing this sudden decline with the gold torches that are so popular. They look vibrant for a good period of time and then one day the heads just pop off the skeleton and die.
Don't give up or be discouraged. Keep up with your normal tank husbandry routine and hopefully it pulls through. As reefers, we just have to accept that some critters wont make it no matter what you do. It stinks but thems the brakes. Good luck!
