the only major problemo w/ this is that the Yellow and purple tangs will not get along! They have simlilar (in my opinion virtually identical) body shapes, and thus, they will compeat over territory, no matter how big the tank is. Pick either the yellow or purple (whichever one you really have your heart set on) and then pick another tang with a compleatly different body shape, ex: clown tang, or powder blue tang, to replace the other tang. Hope this helps!