Oxygen depletion in a sealed room

[Confuten1]

If oxygen levels were that low in the room wouldnt the flame on the co2 gen go out?. I dont much about this jus the first thing that came to mind.
intresting subject though.

COnfu...

 

[Buddy Hemphill]

If oxygen levels were that low in the room wouldnt the flame on the co2 gen go out?. I dont much about this jus the first thing that came to mind.
intresting subject though.

COnfu...

The flame didnt go out. But adding fresh air fixed the problem.

co2 is heavier than o2. The burner is in the ceiling.

 

[medicine21]

I also have some doubts that it was a lack of O2 problem. Coming back to the argument "if you can breath, plants have enough O2" makes sense to me. Do we think that plants actually need more O2 that people?

Perhaps, you have some other contaminant gas (maybe from a plastic or the AC, dehu, burner) I don't know. By venting it out your plants were happier. Just a theory...

Any other peeps running sealed want to chime in on fresh air and venting frequency if any?

If you are sucking in air from outside, even periodically, then I guess this defeats the whole "sealed room" purpose.

 

[CelticEBE]

I've never heard of there being oxygen depletion in a sealed room.

Photosynthesis is what occurs with plants. They use co2, water and light and produce sugar and oxygen.

Perhaps by bringing air into the room you dropped your temps a bit. Heat stressed plants can droop.

As stated by a few other people. If you can breathe in the room, there is enough oxygen. Also if there wasn't enough oxygen in the room, there would have been no flame for your burner. Fire can't exist without O2.

 

[Buddy Hemphill]

I have a 5 ton a/c. It doesnt ever get above 75. I have a 4 degree swing.

The burner is in the ceiling.

CO2 is heavier then O2.

So the pecentage of O2 is takes to keep a plant healthy is the same it takes to light up a 5 burner CO2 generator?....

Anybody have specific numbers? ....or are you guessing? I would love to see some real data...well.... really I dont care. I know what worked in my room. But it would be cool to find the data to confirm my suspicions. I just havent been THAT worried about it.

FWIW....I just had the best pull EVER. 2+lbs/candle


The point of the sealed room is environmental consistency. Whatever "consistency" you deem appropriate.....IMHO.

I never said there was NO oxygen in the room. I said my plants are healthier with a shot of fresh air in the room.

I'm stickin to my story until I see I am wrong.

Heres what I mean....if I am "messing up" my sealed room....OK!

 

[Desertboy]

Buddy when you dehumidify the grow room air with your air con removes O2 from the atmosphere with bottled co2 this doesn't happen but when you burn hydrocarbon's it's produces co2+water you then remove the water with your dehumidifier this reduces O2 content even if the plants are 100% efficient at turning CO2 back to O2 in your room.


Some of your precious room O2 gets locked into waste water through combustion.

I feel this is such a good point I should make it again!

Freshening up the air every 90 minutes is never going to hurt and quite possibly save on dehumidification costs.

 

[pussOGbrah]

^^^Desertboy you are on point.

Buddy Hemphill, Im having the exact problems you had and its driving me nuts. I finally unsealed my room and within 4 or 5 days my pllants made a dramatic change for the better. I dont know why i waited so long..

Are you any closer to figuring out why plants need this fresh air?

One thing i have noticed is when my plants get bigger ( i do OG bushes) and my room gets filled in the problem starts fixing itself. Maybe the small plants im taking from the veg room are not big enough to produce enough oxygen to keep their new sealed room balanced.

THANK YOU so much for starting and keeping this thread updated. So far this is the most promising solution to my problem ive found yet. The other option is to completely unseal my room, but that is unacceptable because of summer heat and the fact that i refuse to throw in the towel and let my expensive as hell excel air A/C collect dust in the corner. Your method allows me to keep my co2 and AC setup.

Once the run im on is finished, im going to do a run with room purges on your schedule (or maybe 10 minutes every 2hours). If my plants get back to perfection im going to write "Buddy Hemphill is a genius" on my panda film in sharpie. not kidding.

 

[pussOGbrah]

bump

 

[BDBuds]

Plants use CO2 during the day to make sugars, but during the night they do Cellular Respiration just like animals to burn those sugars and grow. I think the hot water heater is definitely over kill, your burner should be plenty for that sized room. Do you have a ppm monitor controlling the Burner? Y water heater is probably filling the room with co2 during the night, when they need no CO2. Also if you have a controller, it should only run the burner during the day. Its all about the ratio of oxygen to CO2, plants don't actively pick out what they need from they air, so you ned to provide them with the right gas in the right ratio. long story short More CO2 less O2 during the Day Less CO2 more O2 during the night. preferably no CO2 at all at night .

 

[Racker]

:)
Plants use O2 @ night.
Plant make more O2 in daytime than they use @ night (that's why we survive on this planet)
When you remove O2 @ night, than that is no good idea.
Roots need O2 but that's in your water (or you add H2O2 when it's not)

Did you ever consider Ethylene fumes?

 

[pussOGbrah]

Hey racker pretty sure it is ethylene (plus sulfur dioxide). This makes sense because the molecule is to small to be scrubbed by recirculating filters.

After lots of headaches i think i know what is causing the problems in sealed rooms. When the co2 burner comes on in a tightly sealed room, oxygen is depleted. Small plants are unable to make up for the depletion and can't maintain oxygen levels at atmospheric levels (20.4%). With low oxygen incomplete burning of propane may occur causing ethylene and sulfur dioxide to be produced.

In a totally sealed room, their is no room for any combustion by-products besides co2+heat+water vapor. Just because you can breath does not mean oxygen is high enough for 100% combustion.

"Without enough oxygen, complete combustion does not occur. This results in dangerous levels of ethylene, sulfur dioxide, and other gases. Without fresh air, burners shut off when oxygen levels are ≤ 18.9%. Humans begin to experience discomfort at ≤17%oxygen.Oxygen can become depleted in 2 to 3 hours and lead to incomplete combustion when there is no venting and cold night temperatures require continual heater operation (Bartok, 1992)."

That quote is from this article, which is an interesting read for anyone experiencing sealed room issues...
http://www.hort.cornell.edu/mattson/leatherwood/

And,,
http://www.greenhousegrower.com/article/19876/ethylene-in-the-greenhouse

 

[Racker]

:)

Is the flame in your burner blue? When burning a little yellow you need oxygen. Another thing people forget...Your burner must burn for at least 10 seconds to allow complete burning of propane. In some growrooms the co2 burner burns for only 1 or 2 seconds and goes off again when dosing at the set ppm level. This also causes the flame to produce ethylene and co.

Maybe you can dose pure co2 from a tank in the first couple of weeks? Ethylene also vapors from glue in wooden boards and some plastics.

 

[Mississip Hip]

If I read this right.....

the ethylene is produced every time the burner starts. BUT.. after 10 seconds, you get a clean flame?

 

[Racker]

Depends on your burner and enviroment. Just look at the flame and you know. It never burns good at the start. I could be 2 seconds or 10seconds. But yes every time it starts burning. This is not so much of a problem when the burner goes on ones in a while.

When the burner goes on>off>on>off>on>off all the time, and it burns for just a short time, it could give a problem. It's better when the burner is on for at least 10seconds or so and the ppm's go a little over the setpoint than to let pendle around the set point all day.

 

[Mississip Hip]

isn't ehtylene what they use to ripen tomatoes?

I think it would take a shitload of cycling in a 4000 cubic foot room to effect anything....I would think. Unless a small ppm of ethylene is harmful to the plants.

How much ethylene does it take to hurt a plant?.....hmmmmmm.....who the hell knows that?!?.....lolz

Great ideas!....

 

[Ythor]

isn't ehtylene what they use to ripen tomatoes?

I think it would take a shitload of cycling in a 4000 cubic foot room to effect anything....I would think. Unless a small ppm of ethylene is harmful to the plants.

How much ethylene does it take to hurt a plant?.....hmmmmmm.....who the hell knows that?!?.....lolz

Great ideas!....

Many plants are sensitive to ethylene at the part per billion level. The precise symptoms depend upon the crop; carnations are pretty much ruined by 1-10 ppb ethylene.

For cannabis, ethylene probably "reinforces" gender, pushing plants towards females. Colloidal silver is used to produce male flowers on female plants- probably because silver catalytically destroys ethylene, cracking that double bond.

However, this does not mean ethylene is intrinsically good for cannabis, and it is possible that too much ethylene causes problems.

 

[dankworth]

I believe that I have experienced unhealthy levels of ethylene buildup in sealed rooms. Unhealthy for both me and the ladies.

My halfass plan to address this is to have a filtered exhaust and intake fan run for 15-30 mins once per night cycle to exchange the air in the room. Would be using electronically controlled dampers mated to the exhaust and intake fans to prevent backflow of outside air into the sealed environment when not in use.

Some shit like this.

 

[Racker]

Ethylene is the stuff that your plants need to flower. (ripen). When you have ethylene in your room in week 1, the plant starts flowering in week 1.

The leafs turn yellow and leafstalks purple and you finish 3weeks later with bonzai cana. It effects the plants direct under the lamp the most. (don't know wy)

 

[pussOGbrah]

"If you suspect ethylene is present, the first thing to do is verify there is indeed a problem. One of the easiest ways to detect ethylene is by using indicator plants. These are plants so sensitive that they respond dramatically, even at concentrations as low as 0.01 ppm.

Cuphea and tomato both make excellent indicator plants. Cuphea will abscise all of its flowers (Figure 2), and tomato will bend its leaves downward as if they're wilted - but they will remain turgid (epinasty) when ethylene is present even in very low concentrations. Such responses usually show up within 24 hours of exposure, although lower greenhouse temperatures can slow the response."

^^^^^Quoted from the second article I posted.

 

[pussOGbrah]

I believe that I have experienced unhealthy levels of ethylene buildup in sealed rooms. Unhealthy for both me and the ladies.

My halfass plan to address this is to have a filtered exhaust and intake fan run for 15-30 mins once per night cycle to exchange the air in the room. Would be using electronically controlled dampers mated to the exhaust and intake fans to prevent backflow of outside air into the sealed environment when not in use.

Some shit like this.

Hey dankworth, I setup an intake/exhaust for my sealed room. I now purge 10 minutes every 3 hours (20 minutes every 3 hours at night).

Sentinel controllers (cppm1) have a connection where you can hook up a 12volt "trigger" connected to a wall timer. when timer comes on, burner turns off and stays off till timer turns off. I have this coordinated with the timer my exhaust fan is plugged into.

Those electro dampers are nice, but very expensive for what you get. I use a cheaper 10 inch back draft damper from can filters for my exhaust fan. I have two 8'' intakes, and these have 8"" dampers-- from CAN as well. No air (stink or c02) escapes at all. Something to consider.