How many cfm's ?

I'm building a new stealth cab and need some definitive answers on fans and ventilation. the cab is 4'x2.5'x6' with a total of 60 cub ft. I plan to do a cool tube on a 400w hps and will need a scrubber. How many cfms does the cool tube fan need to be and how many cfm does my scrubber need to be ? any help or comments would be greatly appreciated.

I don't see how your going to fit a carbon filter in your growing cabinet. Your cabinet is quite small, with having a cool tube, & hosing, you might be better off to push the air out of the room and into a carbon scrubber that sits outside of the room.
You could probably go with a tiny 4" inlet carbon scrubber that's only 18 inches in length. But you would have to get a tiny blower, one that's rated at only 110cfm's. I don't think that would be enough to cool your light and a pull air through a carbon scrubber.
What you could do is get 2 - 110cfm fans and have the scrubber and the cool tube on it's own seperate blower. That's the only way I can see it working effectively.