Ok here goes. I've got a 3m x 3m area.I want to add co2 but need to solve this humidity issue and get everythin dialled in first.I'm running 6 x 600w hps.Air is moved by 3 oscillating fans and also air is ducted out of the room at point A and re-enters at point B without leaving the ducting, effectively just mixing the air some more as I want my room completely sealed.I have a dehuey running 24/7 and condensation is still forming on the inside walls. Any help or input greatly appreciated as this is the first attempt at sealed I've done. Temps are 90 by the end of lights off (bit high but ok with co2) and plants aren't showing any signs of heat stress.) lights off temps can sometimes get as low as 65 but are normally above 70.Anyhow, Where is this condensation coming from?I first thought it was getting cooled too fast in the ducting and condensing and getting thrown back in the room so I did a little experiment. I moved the ducting and everything inside the room so there was no dramatic temp change in the ducting to condense the humidity and thought this would solve the problem. Long story short, I was wrong. Where is all this humidity and condensation coming from and how the hell do I get rid of it?And if I can't what's the most efficient way of running co2 with the conventional intake exhaust method?Thanks for any input in advance.