MH bulb 7.5 inches off water surface ok?

[Joshsmit56001]

With the hood that I am in the process of building, the furthest I can get the bulb off if the water surface is 7.5 inches. I am placing 3/4" spacers between the reflector and the top of the hood to allow for air flow. If you think I chould scrap that Idea to get the bulb higher off of the water surface I can do that too but I thought it was a good idea to have the air flow to cool off. Also I have to place the parallel to the front of the tank. Will this be ok too? Please let me know what you think.

 

[captivereefs]

Everything sounds OK. 8" is where i like them but i do not think 1/2" will hurt.

 

[something_fishy]

7.5" is perfect, I've seen them as low as 6", but that might be pushing it, you will tell very quickly if it is too low, your temperature will rise quite rapidly if it is in the "kill zone"