Airpump location and CO2 Enrichment - Fact or Fiction?!

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medicine21

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It seems there is a consensus that if you are adding CO2, you should either locate your airpump higher in the growroom or outside the growroom entirely.

The thinking behind this is that roots needs O2 and do not like CO2. But what are we talking about here in terms of real numbers? Atmosphere contains about 21% Oxygen and 0.039% CO2, so that is 21,000 PPM of O2 and 390 PPM of CO2.

Okay, so now I boost my CO2 with a nice propane burner and bring that up to 1500 PPM or 0.15% of my growroom atmosphere. This is now feeding into my reservoir and DWC buckets. 0.15% vs 20% or so of O2. 1500 PPM vs 20,000 PPM. Number-wise seems insignificant. This will have some kind of negative effect on my roots/plants? What kind exactly?

I get the feeling this is one of those "he said - she said things" - a myth. Has anyone performed any actual experiments that showed higher CO2 levels to rootzone detrimental AND/OR improvements when relocating the airpump for lower CO2 concentration?
 
Papa

Papa

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medicine21, you mention locating the pump higher in the room. i believe this is to address a separate issue, if the pump should go off and it is down low, there is the possibility of water syphoning back through the airlines and draining buckets.
 
motherlode

motherlode

@Rolln_J
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yes you should always have the airpump higher then the water level

if you think its a myth them try it - seems more like comnon sense to me
 
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medicine21

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medicine21, you mention locating the pump higher in the room. i believe this is to address a separate issue, if the pump should go off and it is down low, there is the possibility of water syphoning back through the airlines and draining buckets.

This is true as well, but also because CO2 is heavier/denser and drops to the ground. So the theory is that there is a higher concentration of CO2 on the bottom and O2 on the top. At the same time I was just reading the Fatman thread on dissolved oxygen and according to him the O2 concentration in the atmosphere plays no effect on resulting DO levels as they are two different things.

yes you should always have the airpump higher then the water level

if you think its a myth them try it - seems more like comnon sense to me

Agreed, for the power out issue and syphoning. But I am not convinced on marginally higher CO2 entering the water through air difuser being detrimental to root/plant health.

And yes, I have my airpump in a CO2 enriched room.
 
motherlode

motherlode

@Rolln_J
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I hear ya - need a meter first to see if it decreases the amnount of DO

and then a side by side run to see if it effects the growth rate
 
T

Th3Jungl3Boy

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I hear ya - need a meter first to see if it decreases the amnount of DO

and then a side by side run to see if it effects the growth rate

I completely agree with you. But it seems like no one until now brought up those results making it hard to assume that the air pump should be kept outside.
If we knew the result of keeping it in the room would be nice because I will make a test keeping mine inside so you guys can follow the progress & see by yourself if it's causing any issue.
Peace!
 

MMRC Grower

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I doubt that it makes any difference. Plant roots are capable of breathing oxygen in hard, clay like soil. So if they can breath in that, Im sure they can breath just fine with boosted CO2 levels. And if there is an effect, I bet its so minimal that no one could tell a difference. Thats just my opinion though.

And its always a good idea to keep electronics elevated from the floor anyway.
 
click80

click80

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carbonic acid

FWIW...I keep mine away from increased CO2 for another reason that just makes me feel better about this whole issue....if anyone can add to this as I just get the basics, I would definitely appreciate it.

my dad brought to my attention, that he thought having an air pump that is aerating a reservoir of any solution containing H2O would affect ph and also nutrient uptake. The nutrient uptake part is way over my head, my pop is an organic chemist, but the other part I got.

When CO2 interfaces with water it creates carbonic acid which can lower ph.

I found this out on the net....
In summary;
CO2 enters water through interface with the atmosphere and the biological processes of organic carbon digestion and photosynthesis.
Aqueous carbon dioxide, CO2 (aq), reacts with water forming carbonic acid, H2CO3 (aq).
Carbonic acid may loose protons to form bicarbonate, HCO3- , and carbonate, CO32-. In this case the proton is liberated to the water, decreasing pH.
The complex chemical equilibria are described using two acid equilibrium equations.
The first acid equilibrium constant accounts for the CO2 (aq) - H2CO3 (aq) equilibrium. It concequently seems to have a high pKa.
The fraction of the inorganic carbon in a particular form is call the "alpha" and there are simple equation to describe this alpha.
 

MMRC Grower

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My PH stays stable throughout the entire grow and I have my reservoirs in the grow room to maintain good water temps. My room always stays around 1500 ppm of CO2. It actually will slightly rise after a res change, but after its stable, it stays there. The only time I had ph drop on me, is when I got some root rot a while back.

The science behind it makes sense, but I feel that the effects are so minimal, that it makes no noticeable differences. In ph or plant growth.

To create the perfect environment... just mount your air pumps outside of your room.
 
click80

click80

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My PH stays stable throughout the entire grow and I have my reservoirs in the grow room to maintain good water temps. My room always stays around 1500 ppm of CO2. It actually will slightly rise after a res change, but after its stable, it stays there. The only time I had ph drop on me, is when I got some root rot a while back.

The science behind it makes sense, but I feel that the effects are so minimal, that it makes no noticeable differences. In ph or plant growth.

To create the perfect environment... just mount your air pumps outside of your room.

yeah, i am pretty certain you are right...when i had ph fluctuations I was not dialed in like now, i was in hydroton and had other factors which had more effect on ph than I would think that the standard co2 enrichment levels would have...i guess someone could do the (stoichometry?) math and know for sure but yeah i def agree, just thought it was a consideration, i have read some posts from people that cant afford or dont want to buy a proper control and have co2 swings up to 3000 or more, they quote Ed in his book as saying those levels will not hurt plants/people.

I changed a couple things, mainly though is i am using SuretoGrow, and since starting with that and the new setup (new house and totally cool new setup) i have not had to use ph up or down, it drifted down to 5.9 but it ws time for silica blast and tht brought it back up, all the way to 6.0 lol...I am really happy with ph stability, I know some people say that ph swings are good but i like it stable.

oh, btw, you keep your res' in the grow room for temp reasons? i do the opposite so i can let the grow room go up to about 80. I thought that the higher temp with co2 was better? I would love to know if someone has better results or reasons to keep it cooler in grow room. I have wondered about that from time to time, if higher temps w/co2 was better.

sorry didnt mean to go off on tangent...
 
UCMENOW

UCMENOW

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I have had my air pumps in my room for several cycles without any noticable effects on plant growth, I even called CCH2O to confirm this was ok when I purchased my UC systems. They gave the same rational about lifting them off the ground. If my room is sealed with 1500ppm CO2 and adequate air flow then isn't the whole room at 1500, not just the lower regions?

In theory this may be true, but in reality I think it is a myth...healthy plants don't lie...
 
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medicine21

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Good stuff. I think we have yet to find proof that having air pump in CO2-enriched room is bad for the plants.
 
iscrog4food

iscrog4food

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My air pumps have a fitting to fix a hose to the intake so the pump can be in the room and drawing air from somewhere else. The counter side to this is that it pumps air from outside in and if you have a sealed room you are creating positive pressure. What I really would like to know is if Oxygen supplementation in the root zone (using oxygen gas) would help root growth. I am sure it is not worth the risk as aluminum is combustable at increased O2 levels but it would be cool to try.
 
click80

click80

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0601010847a.jpg


in this pick if you look close you can see an airline going into one of the tables. That table has 600s and the other 1000s, the 600s with the air to rootzone has nearly identical growth as the other tables. Not really scientific, but FWIW.
 
B

Badmf

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BTW; there is more oxygen in an outside room and it would be cooler air too, this effects the amount of DO. If you could take cold air from winter outdoor areas or a refridgerated space it would increase the DO level siignificantly. (Cold air is denser and will help lower the water temperature increasing the amount dissolved)
The grower comparisons aren't really valid as each room has many many factors that are in flux and are different sizes, plant numbers and sizes, light values, nutrients used, ambient temps and humidities and so on.:) Peace Bad...
 

MMRC Grower

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yeah, i am pretty certain you are right...when i had ph fluctuations I was not dialed in like now, i was in hydroton and had other factors which had more effect on ph than I would think that the standard co2 enrichment levels would have...i guess someone could do the (stoichometry?) math and know for sure but yeah i def agree, just thought it was a consideration, i have read some posts from people that cant afford or dont want to buy a proper control and have co2 swings up to 3000 or more, they quote Ed in his book as saying those levels will not hurt plants/people.

I changed a couple things, mainly though is i am using SuretoGrow, and since starting with that and the new setup (new house and totally cool new setup) i have not had to use ph up or down, it drifted down to 5.9 but it ws time for silica blast and tht brought it back up, all the way to 6.0 lol...I am really happy with ph stability, I know some people say that ph swings are good but i like it stable.

oh, btw, you keep your res' in the grow room for temp reasons? i do the opposite so i can let the grow room go up to about 80. I thought that the higher temp with co2 was better? I would love to know if someone has better results or reasons to keep it cooler in grow room. I have wondered about that from time to time, if higher temps w/co2 was better.

sorry didnt mean to go off on tangent...

I try to keep my room around 76-78. On hot days it will go a little above 80. But my res temps are always about 10 degrees cooler then the room itself.

Plants have to work harder to stay cool if your temps are up and RH isnt there with it, which means more water uptake and evaporation. You can go up to 90+ degrees with a Co2 enriched environment, but I would suggest letting your temps get that high, unless you want fluffy, airy buds.

I like to run my room a little cooler. In a range that I would be comfortable at. Then enrich it in Co2 and maybe raise the temps just slightly by a few degrees.

If you keep your room at 80 degrees, then hit them with 67-73 degree water, the plants done seem to like that much. I look at it as it being a hot day outside, then someone throws a bucket of ice water on you. You'll go into an initial shock, then get use to it. So I try not to let me res temps drift too much away from what the room temperature is.
 
click80

click80

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BTW; there is more oxygen in an outside room and it would be cooler air too, this effects the amount of DO. If you could take cold air from winter outdoor areas or a refridgerated space it would increase the DO level siignificantly. (Cold air is denser and will help lower the water temperature increasing the amount dissolved)
The grower comparisons aren't really valid as each room has many many factors that are in flux and are different sizes, plant numbers and sizes, light values, nutrients used, ambient temps and humidities and so on. Peace Bad...

The reason I do this, I should have pointed out, has nothing to do with DO in nute solutions...it is because of studies, controlled studies done where it was shown that O2 infused media produced consistently higher weight dry mass (minus roots) in Hydroponics than just an aerated reservoir. Im just covering my bases, got plenty of extra air and 5 cents worth or microtubing, yeah makes me feel better for sure. Until i can get a brix meter and a DO meter then i can experiment my little ass off...

I try to keep my room around 76-78. On hot days it will go a little above 80. But my res temps are always about 10 degrees cooler then the room itself.

Plants have to work harder to stay cool if your temps are up and RH isnt there with it, which means more water uptake and evaporation. You can go up to 90+ degrees with a Co2 enriched environment, but I would suggest letting your temps get that high, unless you want fluffy, airy buds.

I like to run my room a little cooler. In a range that I would be comfortable at. Then enrich it in Co2 and maybe raise the temps just slightly by a few degrees.

If you keep your room at 80 degrees, then hit them with 67-73 degree water, the plants done seem to like that much. I look at it as it being a hot day outside, then someone throws a bucket of ice water on you. You'll go into an initial shock, then get use to it. So I try not to let me res temps drift too much away from what the room temperature is.

Right on...thanks for that, I am going to start keeping them lower tonight, kinda funny that gut feelings are usually right about growing this stuff...

I keep my RH up on purpose. I read a thread on here and found some studies done on a thing called Vapor Pressure Deficit. My take on it was exactly what you pointed out, in essence wasted energy by the plant that should be directed into photosynthesis. I feel that anything that optimizes P'synthesis is what needs to be focused on.

When I first used CO2 in a tent and I could not keep my humidity down and everyone told me I was screwed. That is when i found a thread on here about VPD and then found more stuff online. That grow ended up being great. The only thing to be careful about is bud mold, but someone, I think Seamaiden told me to keep good air circulation and keep your plants clean it should not be a problem, and it never has been for me, but i do live in a very dry mountain climate.

How do you keep your res temps that much cooler than ambient if you dont mind me asking? I am lucky enough that I have the room in my new place to have the res' outside the grow room. I am always open for info though cause I might need it oneday, so I would like to know if you have like a big res or what?

I read on here that some peeps are cutting a 4" hole in res top and installing a pvc fitting and attaching a computer fan to blow on top of nute solution and this would cool it up to 10 degrees cooler. I did a little experiment and propped my res lid up and tilted one of my fans on it and it did cool it down 5 degrees in 10 minutes.

I am going to remember this for the future, but since i agree with you about shocking roots, I am cool with my res temps at 72-74. I know i have good DO with my method as a friend of mine borrowed a DO meter from school several different times and has measured my res DO on several diff occasions...i keep a steady 8ppm in res and in my table (we measured during first flood and after 3 consecutive floods with no appreciable drop). I use 2 12" airstones per res on a Commercial Airpump 5 and puts out 88lt/min. When i was using my chiller, I MOST DEFINITELY observed epinasty (down canoeing of leaves) at 68 degree nute solution. So, given that this is a indication of low DO, I sorta came to the conclusion that just cause the DO is there might not mean that it can be used if the roots are fucking shocked out of their little Rhizo-wits...lol

I know that i people use water that cool and I am sure it works for them, but with my strain of bbc, and my deathstar, it does not.

Anyway im rambling, thanks for the info and the post and in advance if you repost..

peace

shit, guess i should start or add on to another thread, I apologize for jacking the thread people
 

MMRC Grower

Guest
How do you keep your res temps that much cooler than ambient if you dont mind me asking? I am lucky enough that I have the room in my new place to have the res' outside the grow room. I am always open for info though cause I might need it oneday, so I would like to know if you have like a big res or what?

I have 75 gallon, flat reservoirs that sit on a cold concrete floor. Since they are wide and flat (only about 14" tall), there's more surface area in contact with the cold floor. Also since warm air rises and cold air sinks, and they are sitting under flood tables, out of light, they seem to stay about 5-10 degrees cooler then the rooms temp.

The air pump I use is a 70 lpm commercial pump, that sits right next to my intake fan and underneath my air conditioner. I tend to steer clear of the 12 inch air stones. I like the air cylinders much better. They produce smaller bubbles oxygenating the water much better in my opinion. If you put your hand on top of the water in my res', its like a freshly carbonated soda. Seems like its sizzling, but just with oxygen, instead of carbon dioxide like a soda. Also, the flat 12" air stones accumulate build up over time and tend to clog. The cylinders stand upright, and its pretty tough for those to get clogged since residue floats more to the bottom, then sticking to the walls of the cylinder.
 
click80

click80

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Originally Posted by MMRC Grower
I have 75 gallon, flat reservoirs that sit on a cold concrete floor. Since they are wide and flat (only about 14" tall), there's more surface area in contact with the cold floor. Also since warm air rises and cold air sinks, and they are sitting under flood tables, out of light, they seem to stay about 5-10 degrees cooler then the rooms temp.

The air pump I use is a 70 lpm commercial pump, that sits right next to my intake fan and underneath my air conditioner. I tend to steer clear of the 12 inch air stones. I like the air cylinders much better. They produce smaller bubbles oxygenating the water much better in my opinion. If you put your hand on top of the water in my res', its like a freshly carbonated soda. Seems like its sizzling, but just with oxygen, instead of carbon dioxide like a soda. Also, the flat 12" air stones accumulate build up over time and tend to clog. The cylinders stand upright, and its pretty tough for those to get clogged since residue floats more to the bottom, then sticking to the walls of the cylinder.


Thanks for the info, I have often wondered about using those types of res' instead of the tuff boxes that i use. The cylinder type airstones i have seen and thought about trying and a store in a nearby town has them. I will give it a go. Thanks a bunch for replying.

To iscrog4food
My air pumps have a fitting to fix a hose to the intake so the pump can be in the room and drawing air from somewhere else. The counter side to this is that it pumps air from outside in and if you have a sealed room you are creating positive pressure. What I really would like to know is if Oxygen supplementation in the root zone (using oxygen gas) would help root growth. I am sure it is not worth the risk as aluminum is combustable at increased O2 levels but it would be cool to try

I didn't see the end of your post the other day when posting or i would have PMd you about what i am doing in this grow. I am not using pure O2 but air from the room adjacent to the grow room.

Okay I think you will find this is interesting, I have 2 tables in right now, one under 1000s and one under 600s, Lumatek 1000 wt ball and Phantom 600s. I am using STGrow in both, I have clones from same mom from same batch in both tables. Everything is the same except for lights, and I have 1/4" microtubing in the outside drain channel in the table the 600s are over which i pump air into during lights out and periodically during lights on. I keep daily ph and ppm readings on a chart. The table with the air under my STG mat eats nutes the same as the other table. Day before yesterday I turned off that O2 supply. Since then, as of this mornings readings that table has dropped its nute uptake by...50%. I turned it back on this morning at lights out and will see if nute uptake goes back up. I am using the same ppms in both tables so osmotic pressure on the roots are the same. The other table has kept eating a consistent 90-100ppm/day of nutes. I am in week 4 of flowering, actually day 22.

I am pleasantly surprised by this, but I did read a paper where they had found this same result in greenhouse flowers and (i think) roma tomato's which is why i tried this in the first place.

Has anyone else ever tried this?
 

Jalisco Kid

Guest
Replacing O with co2 in the root zone will lower your plants immune sys. Just like a person they look normal till shit hits the fan and then they can not protect themselves as well. If you did 2 side by side for 2 years and then looked at the ease of growth and weight I would bet the pump outside the room would do better and you would kick yourself in the ass for fighting an idea about running 10-15' extra airline. JK
Then you have the bac and fungus to think about.
 
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