Revisiting problem of rising CO2 at night

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Warrioreuel

Warrioreuel

I know there are several growers out there that have expressed concern over rising CO2 levels at night. Let me save a lot of time here and be very to the point. Originally i had CO2 levels rising to 1500 at night and returning to the daytime normal of 500 shortly after lights came on and the plants ( healthy in the middle of flower stage) started consuming the CO2. I have some old posts on this with more details. Now its gets interesting. Same room seedlings only a few inches tall, hydro grow, hydroton media, compressed CO2 tank, LED lighting, panda plastic on OSB walls painted white, concrete floor 1 year old. After transplanting them to their new home within a few days they took a nose dive. Upon further investigation the CO2 level was 3000 ppm. This obviously will kill a seedling. The CO2 tank in the room was already runed off as no additional CO2 is needed when plants are so young. In fact i completely removed the tank surmising it was leaking thereby causing CO2 level to rise. No affect. The door has been open a foot now for a week with a small floor fan bringing in outside air. The CO2 levels still hover around 450 to 550 ppm. I checked the CO2 sensor in another area and it works fine. Something in that room is emitting CO2, continuously. The OSB walls, painted with Valspar latex paint a year ago, the panda plastic, the hydroton stones, the plastic containers over a year old now, the bare concrete floor a year old, the fiberglass insulation? I am at a loss as how this much CO2 could still be in that room. I drained half the system (about 50 gallons) and replaced it with fresh RO water as the existing water i assume was ladden with CO2 as I had been unknowingly aireating it with 3000 ppm CO2 air, poison. I have ordered some CO2 absorbent crystals that i will hookup to filter the air being bubbled into the water. Maybe this will help. But, i really need to locate the source of the CO2. Any ideas? Anyone?
 
Jimster

Jimster

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When the lights are off, the plants use Oxygen to grow with, and expel CO2... the opposite of what happens during the lights on period. It isn't as much O2 usage as they make during the day, but if you have a sealed room, the CO2 could accumulate at night, especially if there is no air exchange. Hope this helps!
 
Warrioreuel

Warrioreuel

Read carefully. The room has 3 inch tall seedlings. 12 seedlings are not going to raise the CO2 level in a 10x20 room with 12 foot ceilings. The CO2 is coming from somewhere else yet to be identified.
 
Aqua Man

Aqua Man

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Did you work on any equipment in your house? Furnace, gas hot water tank? CO2 will accumulate at the lowest point because it is a heavy gas. Do you use a gas stove propane stove upstairs. Almost anything that consumes fuel will create CO2 and it will travel to the lowest point in your house. Possibly gas dryer vent leak? The list goes on. Check all Gass appliances and their exhaust systems
 
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Burned Haze

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You obviously have a bad co2 controller and it’s allowing it go to high? I had a buddy who argued and argued there was some leak or some neighboring person using a application that gave him a spare controller to test this . He set it to c02 setting max 1000, min 900. Well when I brought over mine and tested it his wasn’t catching shit and letting co2 full blast I not only in efficient but dangerous ) after the new controller . He hasn’t had that problem since and I’m glad it didn’t kill him
 
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Burned Haze

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Actually sorry for double posting but wanted to be correct and wanted everyone to know the correct ppm & proper levels . I looked at few websites and this is what I got ( sorry for w/e I thought 5,000ppm was deadly lol)


CO2
250-350ppmNormal background concentration in outdoor ambient air
350-1,000ppmConcentrations typical of occupied indoor spaces with good air exchange
1,000-2,000ppmComplaints of drowsiness and poor air.
2,000-5,000 ppmHeadaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
>40,000 ppmExposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.
 
Aqua Man

Aqua Man

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Actually sorry for double posting but wanted to be correct and wanted everyone to know the correct ppm & proper levels . I looked at few websites and this is what I got ( sorry for w/e I thought 5,000ppm was deadly lol)


CO2
250-350ppmNormal background concentration in outdoor ambient air
350-1,000ppmConcentrations typical of occupied indoor spaces with good air exchange
1,000-2,000ppmComplaints of drowsiness and poor air.
2,000-5,000 ppmHeadaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
>40,000 ppmExposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.
Awesome info
 
Jimster

Jimster

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Read carefully. The room has 3 inch tall seedlings. 12 seedlings are not going to raise the CO2 level in a 10x20 room with 12 foot ceilings. The CO2 is coming from somewhere else yet to be identified.
Sorry for the oversight. Is there any chance of a chemical reaction or fungus/yeast growth?. The reaction between something like sodium bicarb, often used for raising Ph, and something acidic, like you often see from hydro setups that run lower Ph ranges, can release CO2 as part of the reaction between the two. Cement floors and acidic liquids? Decomposition of Formaldehyde in OSB products? I have to admit... you seem to have covered all of the bases except a sizable algae growth in the res tank (Very unlikely) or some other type of biological growth, since it seems to be light dependent.
Does the CO2 only rise during the lights off period, or did I miss something again? Is there anything else that happens when the lights turn on, like fans or something like that? I'm scratching my head to figure out what would cause the CO2 levels to rise only at night... unless I misread it and the CO2 level goes high regardless of lights being on. Strange.
 
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Deadstill

Deadstill

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Is this room in the basement of your house, or below ground, by chance? And do you happen to live on old farm land? How about your A/C, is it functioning properly? There's definitely something going on. I find this very intriguing! In a sense, I wish I had this problem :D
 
Warrioreuel

Warrioreuel

Thank you for all replies. This is a metal building I had built. Poured the concrete slab 1 year ago to date. There is no controller or CO2 tank in the room at all, i removed it until i figure out what is going on here. It has 12 seedlings a few inches tall. However, there is 120 gallons of water circulating in a DWC setup with Cal-Mag, Aqua Flakes and nitric acid to keep the PH just under 6. It also get about 150 ml of UC roots once a week to keep away root rot. Since the seedlings are small my nutriet strength right runs approx 120 ppm. This is not my first setup but it is a new grow room in a new area so to speak. The RO water by itself is almost exactly PH 7 with 20 ppm, so its pretty clean. At this point my list of suspects (process eliminatus) is the concrete is off gassing CO2 (or poured on top of a CO2 source bubbline through the floor), the OSB walls, the paint and now possibly the nutrients in the water off gassing (had not thought of that before). So far i have left the door open now for a week with a floor fan and the levels are down to low 400's. If I close the door they will rise so as a stop gap measure i will simply leave the door open for now. CO2 absorbent media hopefully be here this week. When it gets here my intention is to route the air through it before it bubbles through the air stone. I am hoping that this will least scrub my water of CO2 which was most likely saturated with CO2 gas when the room was 3000 ppm. It would be nice to have a device to check to dissolved CO2 level in the water to see if I am actually having any impact with my corrective measures. I suppose recovered healthy plants will be the final indicator but I like to know really what is going on. I suppose if this were a dirt grow then the free CO2 would be fine. But, in hydro it is poisoning my water.
Here are some questions. Is an OSB walled painted with latex a true barrier for CO2 or does it pass through the wall as if it were nothing more than a bug screen? Does concrete retain CO2 like a sponge? In other words when my levels were over 3000 ppm, did the concrete absorb this and now slowly releasing it?
 
Warrioreuel

Warrioreuel

Yes, my A/C seems fine, It is a mini split, works perfect (near as i can tell). Farm land? Actually i was told that the area where my house is located was a heavy wooded forest 20 years ago and totally cleared to build the house.
 
Aqua Man

Aqua Man

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Thank you for all replies. This is a metal building I had built. Poured the concrete slab 1 year ago to date. There is no controller or CO2 tank in the room at all, i removed it until i figure out what is going on here. It has 12 seedlings a few inches tall. However, there is 120 gallons of water circulating in a DWC setup with Cal-Mag, Aqua Flakes and nitric acid to keep the PH just under 6. It also get about 150 ml of UC roots once a week to keep away root rot. Since the seedlings are small my nutriet strength right runs approx 120 ppm. This is not my first setup but it is a new grow room in a new area so to speak. The RO water by itself is almost exactly PH 7 with 20 ppm, so its pretty clean. At this point my list of suspects (process eliminatus) is the concrete is off gassing CO2 (or poured on top of a CO2 source bubbline through the floor), the OSB walls, the paint and now possibly the nutrients in the water off gassing (had not thought of that before). So far i have left the door open now for a week with a floor fan and the levels are down to low 400's. If I close the door they will rise so as a stop gap measure i will simply leave the door open for now. CO2 absorbent media hopefully be here this week. When it gets here my intention is to route the air through it before it bubbles through the air stone. I am hoping that this will least scrub my water of CO2 which was most likely saturated with CO2 gas when the room was 3000 ppm. It would be nice to have a device to check to dissolved CO2 level in the water to see if I am actually having any impact with my corrective measures. I suppose recovered healthy plants will be the final indicator but I like to know really what is going on. I suppose if this were a dirt grow then the free CO2 would be fine. But, in hydro it is poisoning my water.
Here are some questions. Is an OSB walled painted with latex a true barrier for CO2 or does it pass through the wall as if it were nothing more than a bug screen? Does concrete retain CO2 like a sponge? In other words when my levels were over 3000 ppm, did the concrete absorb this and now slowly releasing it?
You can easily check the CO2 levels in your nutrients and I would say from years of injecting CO2 into water it's definitely not from your water. CO2 dissolved in water creates carbonic acid. CO2 is very hard to dissolve in water and quickly moves back towards equalibrium when amounts are above equalibrium. It won't store CO2 like ppl think. You will see ph changes from day to night if this was an issue. I grew aquatic plants for years using a CO2 reactor to inject CO2 into my water and I can tell you its not easy to dissolve in water without added pressure and off gasses extremely fast. To give you an idea of how noticable it is with a KH (carbonate hardness) of 4 to reach 30ppm of CO2 above equalibrium you would be looking at about 1.0 ph drop
 
Scolymia7

Scolymia7

Thanks for the post, it made me look into an issue I've had for sometime. High co2 hasnt been an issue for plants, but for my corals..yes. I have around 500ish gallons of reef tanks in basement and maintaining the ph is a constant struggle. I determined it was from elevated co2 in and connected an air pump that draws air from outside to tanks. This helped(ph was 7.8 constantly, after air pump 8.0) but still struggled to hit that 8.3-8.4. When I left windows open for several hours it would help ph a little more. But after closing ph would lower in hour or 2. Read your post and it made me look up co2 and concrete. Found an interesting read, although it doesnt say how to fix it persay, it tells me that I need to find a way to pull in fresh air on a regular basis and at same time pull air out. Would be nice if an automated device exists for this purpose and not alot of $$$$.

Thanks again, would of never looked into it with out reading your post. Heres the article

 
Deadstill

Deadstill

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Ok the reason I asked about farm land is a phenomenon called "soil capping" where essentially the soil becomes so waterlogged it cannot retain gases anymore and the co2 actually comes out of the ground and will then travel to the lowest point. Sometimes will even come through basement walls so I would say this may be a possibility, though unlikely as it usually happens as a result of previous fertilizer use. However, forest land can be just as rich, so that's why I say it's a possibility. It normally only happens when it rains, though. People have had their pilot lights go out on water heaters and furnaces because the co2 became so thick it actually smothered the flame.

The article above is correct, as well. Concrete will absorb and release co2.

As a cheap, possible solution perhaps you should go to walmart or home depot or the like, and buy a big roll of plastic sheeting. It varies in price depending on how thick it is. Obviously the thicker the longer it will last, so buy enough to line the entire floor and see if that takes care of the problem. You could even seal the edges and corners with some duct tape or something. I bet that takes care of it.
 
Aqua Man

Aqua Man

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Thanks for the post, it made me look into an issue I've had for sometime. High co2 hasnt been an issue for plants, but for my corals..yes. I have around 500ish gallons of reef tanks in basement and maintaining the ph is a constant struggle. I determined it was from elevated co2 in and connected an air pump that draws air from outside to tanks. This helped(ph was 7.8 constantly, after air pump 8.0) but still struggled to hit that 8.3-8.4. When I left windows open for several hours it would help ph a little more. But after closing ph would lower in hour or 2. Read your post and it made me look up co2 and concrete. Found an interesting read, although it doesnt say how to fix it persay, it tells me that I need to find a way to pull in fresh air on a regular basis and at same time pull air out. Would be nice if an automated device exists for this purpose and not alot of $$$$.

Thanks again, would of never looked into it with out reading your post. Heres the article

What I'm not getting from that article is that it absorbs and stores at rates higher than equalibrium. Infact it renforces my point. If CO2 is higher in the air than the concrete it will absorb and if its lower it will release. So unless he had his CO2 at 3000ppm I can't see it giving off those levels as it's try to reach equalibrium. CO2 levels in your house will rise just from people and animals breathing and higher levels will accumulate in basements as the gas is heavier than most that make up air.

What I can see is a chemical reaction when mixing acids and bases. So like Jim suggested possibly acid spills or etching of concrete.
 
Aqua Man

Aqua Man

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Ok the reason I asked about farm land is a phenomenon called "soil capping" where essentially the soil becomes so waterlogged it cannot retain gases anymore and the co2 actually comes out of the ground and will then travel to the lowest point. Sometimes will even come through basement walls so I would say this may be a possibility, though unlikely as it usually happens as a result of previous fertilizer use. However, forest land can be just as rich, so that's why I say it's a possibility. It normally only happens when it rains, though. People have had their pilot lights go out on water heaters and furnaces because the co2 became so thick it actually smothered the flame.

The article above is correct, as well. Concrete will absorb and release co2.

As a cheap, possible solution perhaps you should go to walmart or home depot or the like, and buy a big roll of plastic sheeting. It varies in price depending on how thick it is. Obviously the thicker the longer it will last, so buy enough to line the entire floor and see if that takes care of the problem. You could even seal the edges and corners with some duct tape or something. I bet that takes care of it.
Or concrete sealer I think silicon based liked used for treatment of mold would be ideal but also very toxic so I would make sure to wear proper ppe
 
Aqua Man

Aqua Man

Staff member
Supporter
Ok the reason I asked about farm land is a phenomenon called "soil capping" where essentially the soil becomes so waterlogged it cannot retain gases anymore and the co2 actually comes out of the ground and will then travel to the lowest point. Sometimes will even come through basement walls so I would say this may be a possibility, though unlikely as it usually happens as a result of previous fertilizer use. However, forest land can be just as rich, so that's why I say it's a possibility. It normally only happens when it rains, though. People have had their pilot lights go out on water heaters and furnaces because the co2 became so thick it actually smothered the flame.

The article above is correct, as well. Concrete will absorb and release co2.

As a cheap, possible solution perhaps you should go to walmart or home depot or the like, and buy a big roll of plastic sheeting. It varies in price depending on how thick it is. Obviously the thicker the longer it will last, so buy enough to line the entire floor and see if that takes care of the problem. You could even seal the edges and corners with some duct tape or something. I bet that takes care of it.
Like h2s created in the same conditions from rotting organic matter
 
Jimster

Jimster

Supporter
You mentioned Nitric Acid as an acidifier. If it is mixed with many nutrients, notably carbonates(also found in cement/concrete), the reaction can release CO2, like mixing vinegar with baking soda. The same reaction occurs with just about any acid, and most alkaline materials, such as cement, PH up products, egg shells, limestone, coral pieces... they all release CO2 until they reach an equilibrium and/or neutralize each other. The thing that is still confusing me is why it only happens at night. There is something I'm missing here, since the absence of light shouldn't affect CO2 in any way, unless it is heat related possibly, although I would think off gassing would happen more with warmer temps.
 
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