I do get your point, you do not get mine. If your lights are on, the plant is using co2 during photosynthesis. When the lights go off your controller's photocell should read the lights are off and not fill up the room. Which would mean there shouldn't be as much co2 pumping in the room at night. Any excess co2 left in there during the night will not damage the plant, as the plant can't even absorb any of the co2 in the room. When the lights turn back on for the next cycle, the plants begin using the co2 again. Your AC unit should recycle small amounts of air into the room throughout the day. RH levels can play against you if you have a higher co2 range, but if you have a dehumidifier you're fine. If you have a controller you should be fine if it has a photocell. The co2 that plants produce at night is minimal and much lower than what they actually take in.
