Hmm... Think the stanley alone being hooked up like this would do it?

carbon filter tube > duct > cool tube > duct > intake on stanley. Would that cool a 2' x 4' x 6' flower box with a 400W HPS?

I just didn't want to waste these 4 PC Fans I just bought. I think I will take your advice and use those for circulation inside the box instead of an oscillating fan.