Renting and growing? problems? office space?

my fan is hooked to the same timer as my lights. Its only on when i need to vent the heat, i use the 6 hours at night to let the Co2 build up, then the Co2 shuts off when the lights come back on. In that 6 hour period it may have a chance to build up in the line....or even the house.

Just imagine waking up, sparking a joint.......BOOM.

Yeah, they were running a 2 room set-up with opposite cycles so that the exhaust was always on.On a single12/12 cycle you could have problems with methane build-up. This would be bad as methane is explosive in air.I don'tknow off-hand what concentration it needs to explode,and don't want to find out either.Still it was a slick operation and produced lots of good smoke.