I would like a reef tank with butterflies/ tangs / damsels etc ( yes I know they are called blue devils for a reason ). I plan to have a large tank as wide as deep ( not height ) basically in a large square or slight rectangle with 2 sides visible to the living space and the other 2 in a dedicated mechanical room. 2 seperate reefs in a yin yang orientation Thinking in 1000gal neighborhood . How large should go to allow everyone to have their own territory , not be able to see each other or at least if they chase each other at least give up chasing before somebody gets hurt ???