ell, first off, I know it's not the correct way to ID things, but I have never seen such a green specimen of tubinaria
Second, the tubinaria has a smooth skeleton and tissue between the corallites. This definately has a bumpy texture between the corallites. If this is from the skelton or the flesh I don't now.
From the growth form it sounds ike a montipora sp. but from the picture it appears to be hydnophora. It could also be a merulina sp.