The coral is not in very good shape, being so browned-out, but it looks to be A. valida, with it's strongly appressed radials with tiny corallite openings. This species may actually represent a group of species that are diverging. Some have much smoother surfaces than others. I get the impression that, when they are in a nutrient rich system, they get 'fat' and loose some of their texture (as well as colour). If you maintain low PO4 in your aquarium, it should colour-up pretty quick.