How high for a MH fixture

Is there a proper height for depth ratio for MH lights? My tank is 24” Deep and I am adding a double MH 175W 10,000K Bulbs. I do not think I can hang it from my ceiling since my tank is angled and I may have support problems. I was think of making three wood blocks for it to sit on and need to know how high to make them. LFS said 2” would be fine. Does anyone use a glass top for a MH fixture?

 

Do not mount at 2" if you got glass it will shatter and if not bulb will when water splashes on it. Usual hiegth is 8-10" above water line.
you may want to put a canopy

 

Nugio, i have a Tempered glass top on my aquarium. The MH will be a Custom Sea Life w/ Aluminum Hood, dual fan. Will the MH still heat up the glass top to the point of breaking? What do you mean by a canopy?

 

Does the fixture have "legs" to mount to the  ends of your tank?
2" sounds too low for me.your evap will be high and your water temp may increase to where its uncontrollable.
look at my album the wooden box on top of my tank is the canopy  that one is 6" high my fixture is inside it and its too low still.
when i first lit my MH my lid cracked and the bulb wasnt even up to temp.i got a new custom built one thats my next project after RO unit plumbed to tank.