when is it the best time to run a co2generator in a grow room

i was trying to see when it is best time to run my co2 gen in my room and does it work good for yield iam using 3 1000 and 1 600 hps light with 25 to 30 plants using foxfarm soil and the adding in it iam this trying to figure things out, A lil hope ever hurts

co2 definitely helps if your room is sealed and its used properly. best to be used in flower, but i use co2 late veg and then until week 8 of flower.

ya man thinks man on that

I wanted to ask the same question, when is the best time to run, lights on or off? and also i know that when you run your co2 you want all ventilation off (ducting air out of the room), or it will be wasted. If anyone can answer this also it would be appreciated, (im sure mrmo123) would want to know the same but . . . Once you run the co2, how long should you leave the ventilation off before its safe to turn it back on?

i dont have any air in air out. just have the lights vented through ducting and an inline fan that runs 12 hours when the lights are on. you just got to tape up any air holes in your hoods, my raptors are pretty tight though they dont leak much. i only run co2 12 hours as well, when the lights are on. plants give off there own co2 when lights are off. i start them about 900ppms going into flower and by the time im going into week 3 they will be getting about 1450 ppms of co2 all the way until the last week of flower.

i have air being pulled from outside through the ducting across my lights and then back out the other side of the house. so there no fresh air coming in the box, just across lights. i dont recommend using intake outtake fans at all to keep the room cool if your using co2. get a mini split and control your whole environment, best bet imo. hope this helps

Ok I got you, makes sense, I have ducting connected to all 4 of my lights but the very last light is just an open end, so the inline fan is pulling air out of the room through there, I'll just have to suck air out of a different room then. Thanks.