hey mate, its me again, the question machine :S. its been a while and i`m having a huge progress,but now i have another problem.if you can , can u describe how to build my own ventilation ? i know its annoying question, but i have no idea how to build it.i dont know what parts i need. also my space is 3.5m x 4m. and much this will cost me ?can i do it with less expensive materials or so ? do i rly need air filter and so on... or i can use few vents instead ? i can provide a pictures of the room which i am going to use.