Installed MH height

[Chad]

Ok,

I have a 20gal nano, and I just recently got ahold of a 175w MH that I'd like to use over my tank. I figured maybe have the light about 8inchs above the water. So from the water level to the exact bottom of the bulb itself is 8 inches. It seems pretty high when I measured everything out to rebuild my canopy. My canopy would be about a foot high. It just seems a bit too much to me.

My question I guess is would 8inches be overkill or could I go lower?


TIA