I agree with the recommendation to go with an additional 2x250 or 175w MHs. I would advise against the 400s based on a) power consumption, b) increased evaporation, c) the oops I burned myself again factor.
I used to have 3x 400w over a 30" deep tank, and I didn't mind it then, but it was on the cusp of being too much for the tank. I loved 175w over 18" deep though, it worked amazingly well for me.
Check out Sanjay Joshi's website for more details on ballasts, bulbs, PAR, etc. Its a good place to start if you are sure you want to go with metal halide.
|