As long as it does not heat the water or cause bulb breakage I think you'll be ok. I keep my MH 6" from the water but it's to make sure the light spreads out.
forum community dedicated to tropical fish owners and enthusiasts. Come join the discussion about species,breeding, health, behavior, aquariums, adopting, care, classifieds, and more! Open to fish, plants and reptiles living in freshwater or saltwater environments.