I am deep into flower and constantly battling smell issues that I can't figure out. I have a 171cfm fan and generic 4" carbon filter. With my initial setup I had the ducting set up like this: filter-reflector-fan-outside. I am growing in a very narrow space so there were three 180 turns in that path, I hypothesized this was reducing the fan efficiency enough to not make the filter work adequately. I've spent all week rearranging things and right now it is down to the absolute shortest path, running in a straight line filter-fan-outside. Altogether this stretches over less than 3 feet and it seems to have made the problem worse. I'm buying ona regularly and it helps mask the smell a bit but this is getting to be a pain in the ass. I've also replaced all the ducting and taped the shit out of every joint to make sure there is no air being pulled in without going through the scrubber. Did I just get a shitty filter? thinking of trying one of those odor-sok filters. Also debating an ozone generator, are these effective?