Please, don't select this as the answer, as i am not eligible for the ongoing contest
If you want smell to be contained, you want slight negative pressure, otherwise it will leak into room/house/aparment - which would defeat the whole purpose of a carbon filter. As long as you feel air being pulled in when you open up a zipper, at least initially with a small gap, then all is good. It should not be a strong pull. Simply make sure it's not being forced out when you open it up.
The 200cfm with a filter and hopefully mulple bends in the ductwork, if it can let light in, will ikely make "too much negative pressure" virtually impossible with a typical exhaust fan.