As you see im in a pickle but im not new to growing but new to doing the exhaust fans and filter combos and im having 2x 400 or 600(not sure which have 2 days to make up mind seeds be here within a week).. Ive done a few in door grows but with 1 600 and just had my temps run around 82 high I now that's why im trying to do the fans and stuff.. Well I need to know how I run the ducting and everything.. Were do I put the fan/filter combo before the lights between them ect, how do I use a 8" fan with 6" cool tube??, what size ducting would I then use?? Sorry just like doing things right the first time..lol.. Tent is 4.5x4.5x7 and having 15-20 autos, and I have others going outside but that you never know if your stuff will be there next time you go to check so im going all out this yr to be safe.. Also me getting 1x1000w Quantum Ballast with a 48" cool tube is also a option if that may work better for my situation.. Well im sure im forgetting something but just ask ill get right back at you and please help have 2 days..