Yes, the closest thing to natural sunlight, and MHs can punch down into tanks
deeper than 24" Another alternative is to go with natural sunlight: place
skylights in a south/east exposure over the tank and use your 65w coralifes to fill in. Has everyone seen the Spanish guy's tank on APC that is outside in full sun? Quite a showpiece!

I like the way MHs create dramatic shadows and being able to see ripples on
the surface of the tank reflect on the substrate, plants, way cool. The price of admission is rather high, tho.

Bill