There are different sorts but someone who keeps marines would be better able to answer you more fully as to what the differences are.
Compare it to tropical freshwater - there are different sorts of these too, like species tanks where you keep one sort of fish only, African set-ups (split into further groups like Lake Malawi cichlids, Lake Tanganyikan cichlids etc), tetra only set-ups, livebearer only set-ups, fast flowing river themes, southeast Asian river tank, Amazon rainforest stream etc etc etc