Is exhaust necessary?

[hashASHtown]

I've read and heard from a few people that having an exhaust system is not necessary if you have fresh CO2 being produced. Oh, and is CO2 primarily taken up during nighttime or daytime

[AstralSativa]

<!-- / close content container -->Exhaust is very important. Not only for air exchange, but to keep humidty levels and heat down.

High humidty promotes mold and fungus growth.
High heat causes stringy plants.

Higher needs for Co2 is during photosynthesis. Plants will still breathe at night, but do not require as much, as they are at rest.

Keep in mind the exhaust will smell. Odour control might be of consideration.

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[toastybiz]

^What Astral said.

If you otherwise have no issues with heat, humidity, and/or odor, then you might be able to get away without ventilation if you open the door to the grow space once a day and otherwise pump up the CO2. But it's a lot easier to just vent.

[Rumpleforeskin]

Dont worry about low humidity. The lower the better. Your buds will produce more tricomes to protect it's self from low humidity. You need to have a good AC unit and a CO2 meter/controller in order to not exhust your grow room.

[hashASHtown]

i've got a cooltube light, which uses an exhaust fan to cool it. That air will never mix with my grow room air. So heat is not an issue. I doubt humidity will be a problem either because my main resevoir is closed off from the grow room. I just don't want to hook up a fan because of the noise factor

[AstralSativa]

i've got a cooltube light, which uses an exhaust fan to cool it.

Can you use the same fan to exhaust the grow rooms air?

[hashASHtown]

good thinking, but the idea has already been considered. That would greatly reduce my co2 intake and that fan is only suppose to be on during the time when the fan is on. It could work but i definately feel like I am going to have to add a shitload of co2 and constantly be humidifieing the air. I put half of a long piece of paper towel into like a 1 quart container filled with water and the other half I laid over my fan so as the air would blow through it. due to capillary effect and what not the water travels up the paper towel and then into the air with the fan. By time I woke up, like 11 hours later, that whole quart of water was gone and my grow room had only ever reached a humidity of like 45 percent but had already dropped to 25 percent by time I woke up. If my room is sealed off This surely would have been enough to get the humidity to the right percentage

[AstralSativa]

Dont stress to much about humidity,
Concentrate on cool-freash air in & hot-stale air out.

Depending on the CFM of your fan.
The idea in the picture could provide enough air exchange.