[Logan's Daddy]

Mhmm.. interesting. Plants need co2 when there is light, right? When it is dark and it's time for the plants to rest, they don't need co2?

Yes, but the plants will begin consuming co2 immediately once the lights go on, if the co2 comes on with the lights the level of co2 will not be high enough right away, having it come on an hour before the lights allows allows the co2 levels to build to more appropriate levels.