i use a bake-a-round cooltube with a 400 HPS in a 24x24x48 space so very similar to yours

with less then 1" of space around the bulb for air movement its enough to keep negative preassure on my grow tent, so the walls are all sucking inward - and keep the temps between 70-75. outside temp is the same.

once you set it up youll see how it completely changes the air flow in your grow space and all the air will blackhole towards the end of the bake-a-round.

i use a 4" 172 cfm vortex, probably very similar to the power of your stanley blower.

during the hottest part of the day the pyrex is cool enough for the plants to touch, and the actual HPS bulb is cool enough for me to touch although its still hot, but i can keep my hand on it without getting burnt.

i think it would be a bad idea to add a 2nd exhaust to the cab because that will mess up the air flow through the cool tube.


hope that helps

also: aluminum tape is great for attaching the ducting to the tube, and also good for patching the hole where the cord to your lamp runs through (if thats how your doing it anyway)

show us some pics when you have it all rigged up :hippy: