So I have built my own grow box out of a little closet box about 1' by 2' by 5' high, I have a hole cut into it and a 4 inch muffin fan blowing air out and a little portable desk fan insde circulating the air. Could I buy a carbon flter sheet, like the ones used for home purifier systems and place it on the outside of the fan so that the air being blown out has to run through the sheet first? I was think if I did do this I could also build a little shelf next to the fan on the inside as well and have a little open container of ONA as well, what do you think GC? will this be succesful? Stealth is key and a carbon filter may be a bit too noticable..