I have a garage 20x20 an im building an 8x8 room inside of it I'm going to insulate the 8x8 an puting in a mini split I don't want to run c02 till I get some gross under the belt I am wondering on what to do about intake an exaust do I pull intake air from outside or from inside the garage an do I exaust outside in the attic or in the garage I also have 2 tents i could put inside the 8x8 room then I would have like a lung room not sure what to do never growed like this before only growed in a bedroom with tents before will be runing 2 400watt mh/hps 6inch cool tubes the xxl ones thanks for any info that will help me