Well I cut em taking all the fan leaves off, hang em till the twigs break then trim them and dry for another couple days on a drying rack. Then put em in jars monitoring the humidity and opening and closing the jars until about 62 rh. By which time they are musty and i'm pulling my hair out anyway!
Someone mentioned the nutes. I use canna for hydro and normally keep the ppm at about 1700 during flower and ph between 5.6 - 6.0. My meter does measure 400ppm or so from the tap water though. Could that be causing the problem?
Regarding air circulation, I have the window in the room slightly ajar (only slightly as its winter here atm) with a slight through draft. With one fan blowing over the canopy in the tent and the tent flaps fully open.
Not sure if this is relevant or not but I constantly have to ad magnesium every grow to stop the leaves curling upwards and wilting. Apart from a little boost during flowering that's all I add to the nutes.