Frag tank lighting

[Jen0221]

I'm setting up a 48-24-12 tall frag tank. For lighting I'm going with two 250 watt radium 20k bulbs fired with a blue wave 7 m80 ballast and 4 ati blue plus. Tank will grow out mostly sps. I plan to run the mh for 3 hrs and the t5's for 8 hrs. My question is how high off the water should the fixture be? Also is my light times good?