400W vs. 250W HPS

I have a 70in X 48in X 22in cab and I have been trying to decide whether I should just opt for the 400W instead of the 250W. My only concern is being able to cool it. I have an in-line fan, 256CFM rated Active Air along with a 4in Carbon filter.

Will the 400W be too hot if i run it with a cool-tube in the series of:

carbon filter ----> Cool-Tube -----> 256CFM in-line -----> exhaust


I also have 8, 1" passive in-take holes towards the bottom of the cab.

Think I can pull it off?

Get the 400.

Nice to hear from you Andrew, that's what I was thinking..I just don't know when I'll have enough funds to finish the job and finally get something up and running..we all have dreams, right?

If you use the 40w-50w per sq ft then the 250w should be fine, with the 400w you may be waisting too much energy. But in the long run when you want to get a bigger grow space it will then be better because you will not need to buy a larger light. The inline set up should be able to vent out the heat, if not you can always add more fans but the 256CFM fan should have no problem with such a small area.
Good luck