not sure if u have room, but if u can get your carbon filter to be in line with the hoods, so that the ducting doesnt have to turn it will help and cost you nothing. Ducting taking turns drops the fans ability to suck air as hard out of the room.
Is your room getting a lot of negative pressure from the fan? like is it sucking in the door when u close it or sucking in the sides of the tent? If it is you probably are not getting enough passive intake, are the filters on your air intake clogged? Is your ducting insulated?