Custom light fixture question

[benpoole28]

I have a old 36" coralife fixture with the 150w halide and crappy actinic fluorescent bulbs. I have taken everything out of and plan to use just the fixture housing. I know im putting 2 ati blue plus t5's in it for the blues, but Im not sure about the whites. I have a twin 250w halide setup that i want to put in it, since its already on hand, and goes in the fixture nicely. Is that too much light?

Tank is a 57 gal deep blue rimless, 36" long.

I think one 250w halide would be ideal, but all I have is the 2 bulb ballast. Can I run one bulb off my 2 bulb ballast, or would it overpower the bulb?