I'm setting up a 150g 4'x2'x30" I heard anthony calfo suggest one 400 MHL over two 250s in a lecture. would this be a good idea for me since my tank is short and deep. I would like to have clams and mostly SPS like frogspawn and the like. thanks matt

I am far from an expert but in a tank that wide and deep I think that you would have trouble getting adequate light coverage with only one light unless it was suspended quite high above the tank.

go with 2 !!

1 ... you have a center brace

2 ... manufactures recommend 1 halide for every 2 feet of tank.

i would go with 2 x 250w Reeflux 10k's on electronic ballasts.