Definately a goniopora, alveopora has less fingers on each polyp, and they are thicker. I had one very similar, that reached over 10" fully expanded and was very beautiful. It had baby buds grow and fall off of it, and shortly after started to slowly recede and die. It survived for almost a year before it was finally completely dead, and the babies didn't last long at all.
In other words, I don't know a darn thing about keeping them long term, sorry and good luck!