also you said.....quote>When i turn the lights off i turn everything off , i.e fan filtter fresh air ! Should i or should leave on ??

yes i would leave it on with my grow i used to turn fan of like what your doing was ok but then i done some xtra sealing around door's to cut down lite leak etc they started going bit droopy i was advised to keep them on 24/7 and yes it made the difference
if they are starving from fresh air it would make them sad droop etc