I have to agree with the others above, that clown tang is just asking for trouble. I keep tangs, but in a 180g tank, which I;d say is about, what 720liters or so? They are also the most aggressive tang you can get, it will give you trouble if you add any more fish.
I hate fish stores that say things are fine when they really arent, its so not fair to the buyer and the fish. :-(
Just my 2 cents, good luck!