Metal halides are terrible, just upgraded to some on my 75 and they are not that good. I have two really bright spots in the middle of my tank and the edges of the tank are actually kind of dark. There is also a shimmer effect on the edges that I do not like. When I get to my next duty station I think I am just going to load up the tank with tons of sand to make the tank more shallow and use the flouresent bulbs.