Idea for Carbon Filtered PC Fan - Thoughts?

Ok, so I have been trying to come up with a way to use some 120mm 90CFM PC fans to exhaust a 2'(L) x 2'(W) x 4'(H) Vegging box. I will be using a passive intake and a 250W MH. Here is my idea, what do you think?



The PC Fans would be light trapped and would be exhausting out of the box. The carbon filter will be just inside the box.

I haven't seen many carbon filters with two exhaust ports.

The carbon scrubber is the tube kind with activated carbon inside. I would run a channel from the scrubber to the two fans.