Carbon filters/Carbon Scrubbers

Firstly, this is for a very small scale operation. Its a small growbox about 2 x 2 x 3 ft and its going to have an input fan on the bottom and an exaust fan on top with a DIY carbon scrubber attatched.

I was wondering if it would do any good to place an additional fan with a carbon scrubber/or filter inside the growbox?

I would assume that this would kill some odors before it even went throught the exaust but im just looking for some feedback here, maybe someone whos tried this or something similar before.

Complete overkill. A properly constructed carbon filter on the exhaust is all you need.

For that small of a grow op. I would just put a stove carbon filter on the end of my exhaust vent.
You can buy stove carbon filters for about $5 at any HD.
I'm not sure if it would do any good.