This is the route I would go, pretty good deal too. I have a 1000 CFM filter with a 750 CFM fan just sitting on top of it. It is only recirculating room air in a 12x12x10 room, and I don't even have negative pressure, or an air tight seal in there. It's still early flower, but the plants are stinky enough to fill my house. Within minutes of turning the fan on, I can probably smoke in my room and it would clear the smell quick. I had planned to vent it out of my room and create negative pressure, but haven't needed to yet. My temps were basically perfect and didn't want to mess with anything if I didn't have to. I'll do that If late flower smells are too much for this set up to handle.i think this would work for you, good luck. i wouldnt try any of those fresheners because they arent going to work and if people smell a bunch of fresheners they are gonna be like what smell is he trying to cover up? but thats my opinion..
http://www.amazon.com/Hydroponic-Inline-Carbon-Filter-Control/dp/B0051HDECS/ref=sr_1_3?ie=UTF8&qid=1326077256&sr=8-3