I turned the intake way down. . I also turned the outtake down. We are now sitting at speed 1 on the intake, and speed 5 on the outtake. The prefilter on this one is not dirty. This is a new filter and I have made sure to try to clean my equipment after each grow, as part of the after harvest.
As far as Co2 and my environment goes, I like the box fan idea and I will definitely be using that. I have been looking into growing edible mushrooms as well, but have not mainly because I did not want to distract my focus from growing my autos and other flowers. The door does not have to be air-sealed(and in fact mine is not, I have the typical one inch or so gap between the floor and door). If an inspection were to occur, the only thing that would be checked is 1. I am within the plant count limit. 2. The door to the lung room is locked, and inaccessible by means other than a key or physical damage. Bottled Co2 is definitely a possibility, but I have not known anyone to preach its effectiveness so I have not tried it. If you think it would be worth it, I would not mind giving it a shot. I think the mushrooms ideas is good too. I do not know much about mushrooms, and I just get the ones from the store for steak and such. I would have to do some research but I will definitely look into it again.