So I upgraded my fan Yes it's not pretty, basically kindling wood net, dual layer with activated carbon pellets in the top of the toilet roll. I did a smoke test and the draw is going correct but the usb based fan just can't boost that air through at a quick enough rate... doh. It was a fun experiment but I see now that I will need a decent pc fan hooked up to an AC adaptor to get this done at a bare minimum. This growing stuff is a hoot