MH Lighting and Canopy Questions

[lilredwuck]

Ok here is what I have as of now. I finished the base, finally finished the canopy and now I am on to the lighting part. I have a Hamilton Retro Kit? I know it is a Hamilton, it is just the reflector and 2 bulb sockets. They hold a screw in 175 watt bulb in each one. On the top of the reflector are 4 "chunks" of acrylic or plastic of some sort. Nice and thick. Is this to mount to the canopy? Or is this for air flow between the reflector and canopy? It is a 90 gallon tank 4' wide 18" deep and 24" tall. The canopy is 18" tall. Here are some pictures

I am planning on removing the glass tops and was told I Should make the bulbs around 6" off the water. Here are some questions. Can I add a piece of wood to the top of the reflector to help with rigidty? What are the squares for acrylic on the top of reflector? I plan on using chain to hang the reflector 6" off the OPEN water. How can I protect the bulbs from "the elements"? Is this a good hieght for the bulbs? Would this be enough light? Like the look of the soft corals. You can through in any answer you feel I should know that I haven't ask a question for if you would like as well.

 

[scsinet]

It looks like some aftermarket modifications were done to your hood. I'm thinking the acrylic squares are spacers to allow air circulation, like it was screwed directly to a wooden surface.
6" IMO is a little close to the water for halides. If those bulbs get splashed, they could rupture and you'll be cleaning bits of glass out of your tank. With what I'm seeing here, I'm not sure the effort of trying to put something between the lamps and the tank without causing undue heating is worth it, versus just hanging it a little higher.

 

[lilredwuck]

As I plan to use these chains I guess it will be adjustable, with a little time. What would be a good starting point? Also should I position it in the canopy towards the front or back?

 

[scsinet]

I've tried different orientations and I found that center is what I like best. It's all up to you.
I'd do 10-12" above the water.

 

[lilredwuck]

I was thinking of using the pc lights I have to "help" with the color. Also on my fans how do I know what ac to dc adapter I will need? I don't see the Ma on it. One says 0.21A and the other 0.18A so is that 18 Ma? And why does the smaller fan use more?