Gibbs if you have your box semi sealed you don't need intake unless that is what you are using to cool you room......to me it sounds like you have too much air exchange thus low humidity.....you also say you have a fogger....so why do you need to fill with humid air from outside??Unless I misunderstood you....so you should have your fogger on always exhaust in and out off....only when humidity gets too high you should exhaust, if your box is semi sealed then when you exhaust turns on that will create negative air pressure and suck in fresh air from your intake with no fan needed......
