Vent/co2 Question in Closed System

My grow area is long and narrow and I have seperated the back area and would like to use that for flowering. My question is during the light period I can open up the flowering area to the veg area and they would both be ventalated. But during lights out the flowering area is sealed up without ventalation. Is this ok? Will the flowering plants get enough CO2 from just 12 hours? Should I add additional CO2 during the 12 hours of lights off for the flowering area? I could alway add another vent system to the flower area but really I don't want to if it's not necessary.

It Sound Fine To Me, I Dont Even Use Co2... Check My Gallery...why???usit
6'x4' Around + I Do The Same As U For Venting During Lights On Hours....
Just My Thoughts....dbb. The Measurment Is Plant Size X 3 Plus A 2' Experimental Runner....

Thanks for the info and I checked out your grow journal as well. Very interesting with the juice.

You don't need to waste your co2 at night...it won't do any good. I would just watch the highs and lows to see if you need to add any venting. You could always get a small 4 inch duct fan and have it sucking the flower room air into the veg room. I have a similar set-up except mine is opposite. I have the veg room air go into the flower room, where it then gets sucked through the carbon scruber and out the room.