Canopy building fan advice please

[ttt64]

I am putting together a new 36" canopy that will house 2 96w pc, and two 175w metal halides. I am wondering about the best fan placement and if the fans should be intake or exhaust, or maybe one of each? The canopy will be completly closed and sit directly on top of the tank, so the only ventilation will be via the fan(s).
Any pics or ideas of similar?

Also, I am thinking about putting the ballasts inside also, is this too much heat to displace with fans?

 

[Phyxius]

They can be placed both ways. If you have it completely enclosed like you say your best bet would be 1 drawing air in and the other out. This way the hot air will have a way to exit. If its possible to keep the back open it would be good to have them both blowing in across the water. It will expel the heat and also do some water surface cooling.
Blowing out will also work with the canopy open in the back but you will be crawing salt water moisture out through the fans that can lead to shortened life.

My tanks all have open backs on the canopies and I have the fans blowing in. They are mounted closer to the water than the top and create some surface cooling blowing across the water.......