After my current grow I'm planning on building a second larger grow room. I have a large backyard and I planned to construct a fully sealed and insulated shed in southern California. My question is.. If I use co2 to 1500 PPM with a controller and I dehumidify the air do I need constant ventilation? If the light is air cooled and intake and exhaust for that is isolated from the room I would have basically all the bases covered of why ventilation is important in an indoor grow room right? The reason I ask is because it seems more efficient to keep the best conditions if there isn't constant ventilation drawing in air that is different than the optimal temperature. If the room is completely sealed and insulated. As long as I add co2 and dehumidify the air is there a reason I am leaving out for why I need ventilation? Adding co2 and dehumidifying and having an AC unit kick on on the hottest days seems better than a vent fan running 24/7
Constant ventilation no. It is called a "breather" in that you empty the volume of air on a timed basis. That way the Co2 gets a chance to mix and circulate and you aren't pumping it through the exhaust. However, if your running a gas generator and have big volumes of Co2, then a constant vent would be ok, but you would have to mix the Co2 with the incoming air. The problem with a breather is that it had better be a sealed chamber or stink is gonna leak. That is why you should always have negative pressure on the grow area. IMO
Thank you for that piece of advice. Is a breather necessary if i have a fan moving the inside air around allowing constant temperature and homogeneity if the co2 in the room. I know it sinks but I figured some air movement should mix it well enough. Also I know plants release oxygen is there ever a time high oxygen levels can hurt plants?
Like I said, at some point you are gonna evacuate that volume and replace it. What you do to it like fanning it and adding Co2 may extend the effectiveness, but at some point it has to breath. Use a small or throttled back vent to keep negative pressure at the minimum required to overcome any stink leak is what I do, but my rig isn't a breather. I turn on a timed 4" fan to draw air into the chamber (no tent for me), but not at a pressure high enough to cause a stink leak. Trying to make it air tight enough to make it a true breather just didn't happen.
How many times per day should I "breathe" the room and replace the air. I figure the more times I breathe it the faster I will burn through co2.
You may have to sit down and do some calculations. I seem to recall somewhere it was at least twice an hour. For some reason I think it was every 20 minutes.
I have seen that number too but I'm pretty sure that was for if you are not dehumidifying or adding co2. Based on my limited knowledge of growing seems to me as long as the room is the right temp at the right humidity with enough co2 in the air. I can't see why the air needs to be replaced at all really.
You are forgetting the nitrogen content, unless you are gonna inject that to. Atmosphere of Earth - Wikipedia, the free encyclopedia Co2 isn't that expensive, but if you're convinced, good luck. You might look up what the recirculating air on the space station is made up of and what they add to it. Nitrogen tanks and refills aren't expensive either. The trace element gases start getting pricey.