hey man, just read your thread and thought i'd try to help out.

heres a couple of links to threads with answers to some of your questions.

the one for the carbon filter is the best DIY filter i've seen on this site or
any other. check out his other threads also, he is a very clever guy


http://boards.cannabis.com/indoor-gr...-training.html

http://boards.cannabis.com/grow-faqs...on-filter.html

good luck man, have fun