can u double scrub air

I use a good carbon filter, and I get like a little smell because I am recirculating the air back into the room from tent, and not totally exhausting it from the room. I see where you can buy smaller charcoal activated filters online and hook it to the end of your exhaust. just wondering if anyone else scrubs the air twice with a carbon filter, and then runs cleaned air through additional carbon, for added stealth? Here's the filter that I was thinking of clamping to the end of the exhaust ducting.

http://www.amazon.com/gp/aw/d/B002FPQPRA/ref=mp_s_a_1_24?qid=1434078804&sr=8-24&pi=AC_SX110_SY165_QL70&keywords=hepa filter charcoal 4

You can do it. Just make sure your fan has enough power to pull and push through them within the recommended cfm rating for filter.