I'm not that good with lighting. But it has been my experience that metal halide is the best overall lights.
There are new lights coming out every day it seems and people have ALOT of opinions with lighting.
I suggest using MH lights with a combination of flourecent lights.
Mh lights are the best (in my opinion) for clams etc, but they do have brightness to them that is not that easy to our eyes?
so add flourecent lights with alot of blue spectrum to compensate.
I like this combination. I set the F. lights to come on an hour before the MH lights.
This does not seem to stress the fish much.
Sorry I'm not much help.