Very strong smell

You've got it set up as an exhaust an not an intake right? "You're not blowing air into the tent, but sucking air into it using a negative seal. This should 100% get rid of the smell. If you're filter is over 3 months in use.. some might only pay last 1 grow. But, in saying that. I have an SF filter I use a negative seal pressure. So, your tents sides should bow in a little, don't been blown out by air pressure, "tat would for sure cause a smell" I see your ducting is in the pic running down. Why isn't it connected to the top of your exhaust fan Carbon filter - Exhsust-ducting running from the opposite side and running out the top of your tent. That'll cause a true negative seal. Good Growing.