Co2/ exhaust fan

[Dpender1]

I am adding co2 I have a green air timer for co2
My problem is how do you control your exhaust fan

During time co2 is on help please dont want to waste co2

[MonsterEnergy]

any/all extraction must be turned off to let the plants absorb as much co2 as they can,
running extraction at the same time as adding extra co2 is just pointless

really co2 is only needed in a sealed environments where it's actually needed,
fresh air has plenty of co2 - especially if your extractor/heat is dialed in

[G']

I'm around 4 weeks after flip and my girls are doing fine and are cola'ing up nicely and i haven't used any Co2 this grow at all and i know a lot of guys that don't use it, just saying