I'm building a small 3 foot tall grow box in my room. i need a way to either controle the smell. I cant afford to buy a carbon filter. I've seen videos on how to make a cheep home made carbon filter. I dont know much on the subject. If someone could post a list of materials and where to buy them that would be greatly appreciated. Everything from fan in-take/out-take toobing and filter material. Thank you!!!