With the pfo pendent installed in a cutout of your hood, It's an hqi bulb with a small canopy on it all heat goes up, no heat to tank, I run just as cool with 250 as 2 55 compacts by them selves, I only run 1 fan 4" while the light is on, the bulb is above the canopy, so heat rises light goes down. And the ppfo, the rating of photosynthsis available light on the 250 hqi is at the 400 watt mark, ie. it puts off as much good light as a 400 watt, check out the link below on the performance of the hqi compared to other 250 regular bulbs, my lfs just put 2 on a 200 gallon so 2 would be great on yours.
http://www.animalnetwork.com/fish2/a.../2/default.asp
Email me and I can tell you more about the light and the fixture, it does stick above the canopy, but it can be lower to the water because it has a splash shield/uv glass. Oh, and say you got 8 inches from bulb to water, cut that in half to 4, and even you only 2x the distance to the h2o you 4x the intensity in the tank..............
