Great post GG and good move on the filter. Need to get myself one of those too at some point.
Grow room is around 530 sqft (if I do the maths right ~15sqm) and was thinking of replacing my crappy exhaust fan with a 125mm 250CFM inline fan and a 125mm carbon filter that is around 215CFM though, do you think this is enough and do you think the filter being smaller capacity than the fan would create problems? Ducting will be straight and minimal in length. Fan will be attached to the wall and ducting will be used just to connect the filter to it. I like growing sativas (cause I like smoking em that is ), ceiling is at 3m (10ft) tall and I usually (at least with the fan I have now) have around 70-75% humidity but good temps. (68-75F tops)

Peace,
:hippy: