Sealed grow room with constant circulation, and co2

applepoop1984 said:

hello i would like to start by saying a common problem with rooms running constant exhaust is a lower concentration of co2, not as low as a room with no exhaust but not as good as a sealed room with co2. he problem some people have with sealed rooms with co2 is excessive temperatures. i believe plants can utilize up to 7500-10000 footcandles at 90-85 farenheit co2 with a ppm less than 1200 at a relative humidity below 50% but above 40%. with a sealed grow room all of these factors are much harder to control, while maintaining a consistent level of co2

i think i have a solution and it is a sealed grow room with recirculating exhaust.

1st make sure to seal up your grow room completely. a good way is with duct tape. i envision this in a 3x3x6 ft grow box with three walls and the front being a sheet of pandafilm/mylar/reflectix etc. on one side will be the intake fan or pusher fan, not the most efficient design as far as air movement but necessary to recirculate exhausted co2 rich air. this fan will be on the lowest part of the pusher fan side as this will provide colder air by the means of the exhaust duct acting as a heat sink.

cut a hole in the pusher fan side and install the fan and seal around with duct tapemaking sure there are no leaks.

next we install the puller fan side. install puller fan on the side that is opposite the pusher fan and at the highest pointof the box, even the ceiling of the box is acceptable and preferred as this will be the highest point of the box allowing the most heat to be able to escape and be cooled. secure the puller fan on ceiling or wall opposite the pusher fan and make sure it wont fall duct tape is good for sealing but may need other support such as hooks etc.

now we install the recirculation duct. install ducting the exact diameter of both fans so that the puller fan connects to the pusher fan so you have one fan pushing air into the room and another pulling that same air out of the room in a constant loop.i find its best to run the exhaust duct from the puller fan, behind the box and around to the pusher fan.

now you are done. it is important to be able to control at least one of the fans speeds for most control how ever if you can only use one fan controller make it for the pusher fan as the puller fan will always be limited by the rpms of the pusher. it is even possible to use one fan but make sure it is the puller fan up to to increase upward air movement maximizing co2 uptake

no you have much more control as opposed to running a fan timer in your grow room plus these added benefits:

1 less wasted co2
2 more consistent level of co2
3 ability to control humidity more easily
4 easier temp control
5 less risk of outside pests entering
6 increased air movement in the grow room, co2 is very dense and tends to pool on the bottom so upward air movement and negative pressure are helpful
7 reduced odor

i hope someone found this useful i will be implementing it soon

a side note this setup is intended for co2 only, without co2 enrichment the plants would use up available co2 as well as recirculate hotter air since it is a sealed system

i am still working on how the fan speeds will affect temp humidity etc any insight would be appreciated

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Red1966 said:

If co2 settled out of the air as readily as you think, the first thousand feet of air outside would be all co2 and no life would exist below that level. I suppose if you made your cooling loop 200-300 feet long, it would work as a heat sink, but only if routed through a cooler area. Unless you live in a giant air conditioned warehouse, I don't see that working. All the other fans you mention will exhaust your co2. Activated carbon doesn't dry the air. Silica gell would get used up at an alarming rate. 20 plants give off 2-5 gallons a day of water. 2 gallons = 16 lbs. Hove much water can a pound of silica gell absorb?

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applepoop1984 said:

hello i would like to start by saying a common problem with rooms running constant exhaust is a lower concentration of co2, not as low as a room with no exhaust but not as good as a sealed room with co2. he problem some people have with sealed rooms with co2 is excessive temperatures. i believe plants can utilize up to 7500-10000 footcandles at 90-85 farenheit co2 with a ppm less than 1200 at a relative humidity below 50% but above 40%. with a sealed grow room all of these factors are much harder to control, while maintaining a consistent level of co2

i think i have a solution and it is a sealed grow room with recirculating exhaust.

1st make sure to seal up your grow room completely. a good way is with duct tape. i envision this in a 3x3x6 ft grow box with three walls and the front being a sheet of pandafilm/mylar/reflectix etc. on one side will be the intake fan or pusher fan, not the most efficient design as far as air movement but necessary to recirculate exhausted co2 rich air. this fan will be on the lowest part of the pusher fan side as this will provide colder air by the means of the exhaust duct acting as a heat sink.

cut a hole in the pusher fan side and install the fan and seal around with duct tapemaking sure there are no leaks.

next we install the puller fan side. install puller fan on the side that is opposite the pusher fan and at the highest pointof the box, even the ceiling of the box is acceptable and preferred as this will be the highest point of the box allowing the most heat to be able to escape and be cooled. secure the puller fan on ceiling or wall opposite the pusher fan and make sure it wont fall duct tape is good for sealing but may need other support such as hooks etc.

now we install the recirculation duct. install ducting the exact diameter of both fans so that the puller fan connects to the pusher fan so you have one fan pushing air into the room and another pulling that same air out of the room in a constant loop.i find its best to run the exhaust duct from the puller fan, behind the box and around to the pusher fan.

now you are done. it is important to be able to control at least one of the fans speeds for most control how ever if you can only use one fan controller make it for the pusher fan as the puller fan will always be limited by the rpms of the pusher. it is even possible to use one fan but make sure it is the puller fan up to to increase upward air movement maximizing co2 uptake

no you have much more control as opposed to running a fan timer in your grow room plus these added benefits:

1 less wasted co2
2 more consistent level of co2
3 ability to control humidity more easily
4 easier temp control
5 less risk of outside pests entering
6 increased air movement in the grow room, co2 is very dense and tends to pool on the bottom so upward air movement and negative pressure are helpful
7 reduced odor

i hope someone found this useful i will be implementing it soon

a side note this setup is intended for co2 only, without co2 enrichment the plants would use up available co2 as well as recirculate hotter air since it is a sealed system

i am still working on how the fan speeds will affect temp humidity etc any insight would be appreciated

Click to expand...

applepoop1984 said:

to combat heat im somewhat stumped. my main thoughts are using the ducting as a heat sink but i am not sure abotu how to do this to keep levels below 90 degrees. im thinkin keeping it on the floor should lower temps 1 degree,another would be , and i think this may be the best idea, is to have a small fan mounted on the top of the box pulling both heat and ethylene out. having this fan have less cfm than the puller fan mounted on the top of the box would be best so that it wont pull dense co2 particles out of the room while pulling rising heat out and possibly ethylene


density of co2= 1.98 kg/m cubed
density of ethylene= 1.18 kg/ m cubed
density of air= 1.225 kg/m cubed


so ethylene, being lighter than air, should be getting pulled out readily , and co2, if getting pulled at all should hit the puller fan below the ethylene and heat extractor fan since it is much denser.


now the only problem left is positioning of the heat and ethylene extracting fan, and the recirculating co2 puller fan.


if placed on the ceiling of the box it should leave co2 to recirculate, especially if it has a lower cfm than the recirculating fan.


next would be to mount the fan just above the point where the top of the canopy is . i think this solves all problems
so basically here is a short synopsis:


1 seal box
2 install pusher fan at bottom of the box on one of the 3 walls
3 install puller fan on wall opposite of the pusher fan, just inches above wear you estimate the top of your canopy will be
4 install puller fan with lower cfm than other fans on ceiling of box, opposite the wall of the recirculating puller fan
5 connect ducting to puller fan with dehumidifying cylinder in the middle
6 connect dehumdifying cylinder to pusher fan with ducting
7 cut baseball sized hole on same wall as pusher fan, at least 6 inches above top of canopy, basically close to the ethylene/ heat exhaust fan a picture is now included for clarity

picture!!!! sort of...

View attachment 2680020

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kulakush said:

To ventilate or Not to ventilate?

Many argue that there is no need to ventilate a sealed grow room environment because you can simply supplement CO2 and scrub the air with a carbon filter. They say it's a waste of money to let excess CO2 escape and that there is no benefit in doing this. Then I ask them how many sealed grow room environments have they've built and it's usually only a few.

The proven benefit of a sealed grow environment is that you can control and really dial in the elements of the environment to achieve better results than a traditional open air exchange system. The general concensus is that you can truly achieve better quality and maximize weight with a sealed grow room setup. But are you truly maximizing your results?

While many claim to achieve good or great results with a completely sealed room with no air exchange, and also never experience any issues with plants my experience has shown me otherwise.

I've setup many sealed rooms the exact same ways where I have achieved great results and other times I've gotten different results using the same exact setup in a different place. This has boggled my mind for years of why this may be happening. Some places I pulled my best grows and yields and others have given me moderately average results to my grow standards. I don't know the reason yet why this happens sometimes but I've come to the conclusion that when you take away what's worked in nature for millions of years and then attempt to fabricate it by adding all the known needed elements to properly grow cannabis correctly you would expect to get the same results but time has shown me that this isn't the quite case. I've seen unexplained plant problems, small nugs, plants getting freakish leaf wilt, plants acting weird for no reason etc with sealed grow rooms that all had one thing in common and there was no air exchange. Wether it's bad gases in the environment, like excess ethylene or drowning your root zone with too much CO2 etc who knows. Let all those arguments continue. What I do know is that ever since I started running hybrid type systems all the freak problems went away and I am achieving the results of what one would consider a master grower.

There is a way of getting better results by running a hybrid of both systems. Taking what already works in nature and combining it with what man has discovered with CO2 enrichment and environment control to form a hybrid system that helps keep the known and unknown important elements of the environment at balance is what I found to be the key for the perfect grow room.

A hybrid room that is sealed With CO2 enrichment and at the same time ventilated with a continous exhaust fan running at a much slower rate usimg a dimmer so I don't suck out all the CO2 in minutes so that I can still maintain the proper levels of all the necessary known and unknown elements in the environment of nature was the key to having all these freak issues go away. After doing this I've never seen these problems crop up again. Even though my CO2 expense goes up a bit my yields have been the best ever. The buds just simply get bigger. Hitting over 3+ pounds a light with gavita fixtures. When I didn't vent my sealed room I would get 2.3-2.5 a light. I learned this from a very experienced grower in the San Fernando valley. He is the guy who created the sfv og strain. This is how he does his sealed rooms and hits 3.5 pounds a light on a consistent basis. Every grower out here in the SFV that hits over 3 a light runs theirsealed rooms like this. The first picture is my top buds from my og kush strain using the hybrid system, the second picture is a top bud of the same og kush strain under a traditional sealed grow room with no air exchange. I still don't know the science of why this occurs but what I do know is my results from my past experiences growing og kush and the secretes of the best growers of the SFV which first put og kush strain on the map and made it famousto the rest of the world.

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