For those of you who are growing in a closet or who can't ventilate to the outside and are worried about odor this post may be for you. I use a three pronged attack in my battle against smell and after trial and error I have finally beaten back the odor beast. The three things that finally worked for me are: Stand alone carbon filter w/ attached fan (bought on ebay cost about $130 w/ shipping) http://cgi.ebay.com/8-X-14-ACTIVATED-CARBON-FILTER-ODOR-SCRUBBER-240-CFM_W0QQitemZ120362422626QQcmdZViewItemQQptZBI_HVAC?hash=item120362422626&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50 A DIY odor bucket filled with ONA liquid (cost about $20 to make plus another $20 for the ingredients) http://forum.grasscity.com/general-indoor-growing/249749-diy-odor-neutralizing-machine-step-step.html A roll of activated carbon air filter ($3 at Home Depot) I use the standalone carbon filter w/ attached fan in the room that the grow closet is in. I only turn it on after I have shut up the closet for the dark cycle and after running for 30 minutes the entire room is scrubbed and odor free. I have my lights go off at 7am so by 7:30 am my room is scrubbed and there is no smell during the day. At night I like to keep the closet doors open to keep the temps at 70-75 degrees. I used to have a problem with this because the room itself would stink and that stink would enter the heating intake register and disperse around the house. I bought a roll of activated carbon filter at Home Depot for $3 and taped that to the inside of the heating register and also built a little DIY odor bucket (an idea that I got from this site). The combination of the odor bucket running at night and the little carbon filter in the register completely eliminated any smell from being dispersed around the house and the room that I have my grow in just smells like a spa smell from the ONA. If the ONA smell gets too strong I just turn the odor bucket off for a while and run the carbon scrubber for 15 minutes or so and that makes it perfect. I can totally control the odor either way. So whether the closet is open or closed there is now no more cannabis smell. I grow in a spare bedroom that I use as an office and keep that door locked at all times in case family or the landlord ever stop by. By using a combination of things I can have people over and never have to worry that they are going to smell anything. Hopefully this can help out someone who is struggling to contain smell. I did spend around $175 to win this battle and I am sure there are cheaper ways to go but since I rent this house and did not have the option to cut holes and run ventilation outside I consider it money well spent since security is a top priority for me. If you have any other odor busting ideas please share them. Thanks.