Newbie need help - Flow Question.

Thanks.
Currently, I have nothing inthere yet. Actually, only LR: 200#, LS: 2" and 2 clown (got from a friend, didn't buy though) And my tank is planning to be sps with some carpet and soft (very few just for those fish to get hosted)
The size of the display section is about: 54Lx30Wx25H.
The return was 3 of the ViaAqua 306 (originally 526GPH) but with the hieght iit drived up to main tank, I extimated about 165GPH at the outputs.
Hope this will roughly give you the picture of my tank. Thanks