I've used the vivosun filters and they work just fine. A filter is basically just a can packed with charcoal. I used a 4 inch Vivosun for a year and a half without any odor escaping the tent unless I opened the door. I've upgraded to a six inch setup using another Vivosun filter and there is absolutely no odor unless you open the door to the tent. The guy at the hydro store can rant all he wants about Vivosun but he doesn't know what he's talking about. I've used their stuff for years without any issues at all as have many other growers.
Passive intake for negative air pressure then Filter-Fan-Hood-Exit.
Vivosun tent, Vivosun ballast, hood, and light, Vivosun 6 inch carbon filter, Active Air 6 inch fan hooked to speed controller. No problems at all with the equipment and no smell in the garage unless the tent is opened.
