I think you'll have hassles making this 2 tier for the mh and pc. Better to make it 1 tier - I'm not sure how much light intensity you'll lose in 6 inches of air, but I don't think it's much.
My answer(s) would be , look at commercial hoods, homemade hoods that you know work and ask at other sites with lots of reefkeepers (aquaria central...., wetwebmedia). I have a feeling you're well on the way though |