Do bubbles give o2 to the roots or just kill pathogens?

[FreezerBoy]

'aeration' is the actual air in the bucket, where in other systems, media would be.

Aeration is a verb, not a noun. The air in the bucket is the air in the bucket. Without surface turbulence, there's no exchange. Aeration occurs through the spraying process. Waterfalls are the most effective means of aerating and this is, in effect, millions of tiny waterfalls. The res needs to be aerated but, in aero's case, no extra equipment is required as the process of water delivery provides it's own aeration.

 

[lysol]

So another thought experiment, if you lined a bucket top to the bottom with something like rockwool but you chemically maintained perfect DO your leafs would not fold over from lack of oxy to the roots? This is rather contrived but I'm just trying to wrap my head around this. When you say its impossible to overwater hydro you mean once the roots hit the aerated water body unimpeded via medium, if you have a wet medium such as soil then the oxygen is still uptake via the h20 but the perlite just provides air pockets for the water to re-dissolve oxygen, so basically the plant wants oxygen but it wants it thru a proxy ( liquid ) and not gas?

In practical terms, using for instance, grow rocks, to increase the volume of air in the root space will not necessarily increase oxygen available to the roots. likewise with perlite, there is some point of diminishing returns where active aeration is the only way to increase available oxygen. Is there a limit on dissolved oxygen ( mean imposed on us by physics or in diminishing returns in yield ), this is the main factor that makes hydro yield more and harvest sooner correct? Has anyone pushed this to the edge ( and beyond )

 

[*mistress*]

Aeration is a verb, not a noun. The air in the bucket is the air in the bucket. Without surface turbulence, there's no exchange. Aeration occurs through the spraying process. Waterfalls are the most effective means of aerating and this is, in effect, millions of tiny waterfalls. The res needs to be aerated but, in aero's case, no extra equipment is required as the process of water delivery provides it's own aeration.

respectfully disagree.

original ein geddi aeroponics has no air stone. the air reside in the container itself.
no need for surface turbulence; the oxygen in the space media would be in a soilless garden is all oxygen. the roots can freely take what they want because the container has 100% humidity inside.
so, al of the elements necessry for aero are present: air, water, and nutrients. end.

are you suggesting that the oxygen in the container is not available to roots unless it comes from a machine?
or that the roots are unable to process oxygen in the surrounding humid enclosure?

drill couple holes @ top of container. this is gas exchange w/ environment.

1 pump in a res has proven enough here. however, if a gardener wants to add more oxygen to envirnment, wont hurt.

relevant to need of the plant vs. automation by the gardener; now in a realm of preference.

water itself releases oxygen during transevaporation. in soil/soiless, air pockets are used by plants for oxygen. using the analogy of the need for aeration, plants in soil/soilless mix would simply die because there is no air stone in medium.

additional aeration in hydro may be beneficial, and advantageous, but not a need. in marginally dissentin opinion...

enjoy your garden!

 

[lysol]

are you suggesting that the oxygen in the container is not available to roots unless it comes from a machine?
or that the roots are unable to process oxygen in the surrounding humid enclosure?

THis makes sense but why do we need to keep temps down? When I half shut my door my water goes up to 76 and my plants droop. I assume this is lack of oxygen... Roots are exposed to cold air in my medium I guess they dont want this air only dissolved oxygen

I dont think the plant is sensitive to a machine, it would make sense though that it is sensitive to a liquid vs a gas. can someone please confirm this and also confirm my symtoms, if I let my water goto 76 basically the plant would respond by drooping similiar to over / under watering right?

 

[FreezerBoy]

are you suggesting that the oxygen in the container is not available to roots unless it comes from a machine?

I'm suggesting the oxygen will be used up if not replaced. How is it replaced? By surface turbulence. How is surface turbulence obtained? in your case through the use of sprayers. Every time you spray, you aerate the water. That's why you don't need additional stones.

 

[*mistress*]

...........

 

[lysol]

Ok so if your leaves don't look like theyre reaching for the light, the only thing it could be is UNDER water?

if your nutes are constant <= 74 and well aerated by like 4 air stones with a dual outlet pump on each bucket, there is no way there is root rot right? I took a nap today and when I woke up I noticed a difference, my only variable was half closing the closet door but temps in the nutes were still under ~75, My roots arent thru the bottom of the pots yet.

In hydro pics I notice it looks as if a lot of people's plants look like a slightly overwatered soil plant, why does this happen, just not experienced enough growers / not dialed in? What is the variable that causes this, nute temps?

 

[Albireo]

As temps climbs, the amount of DO in the water falls. Your plants are not getting enough DO as temps climb.

 

[Albireo]

I should say as temps climb the ability for water to hold DO drops.

 

[lysol]

Ok so I am beginning to suspect the plant will get its oxygen no matter what because in soil you can have 90 F temps no problem and obviously the roots still breathe, so I guess plants do take oxygen str8 from the air.

I guess temps are only controlling actual root rot for submerged roots, so temps and aeration only matter if the root is touching STANDING water, in a medium the plant still must breathe, you dont see soil growers chilling their soil

Does this make sense? Just trying to summarize what we ( I ) have learned here, heh

 

[Albireo]

soil is a different beast. In dwc plants get their O2 in the form of DO. As temps rise, the ability for water to hold DO drops. It is critical to have low temps in dwc.

 

[lysol]

What property does soil contain that would eliminate the need for aeration though? I understand DWC needs it I'm just saying that is because roots come into contact with a standing body of water correct? Soil is a different beast because it does not have standing bodies of water ( unless you over water ), I understand that they differ I'm just trying to pinpoint exactly how, like it was stated previously its not like the plant suddenly requires machines because it knows its not in soil, I don't aerate my rockwool cubes either because they are 85% air by volume, so the roots must be able to pull oxygen directly in gas form. The only exception is when h2o is actually sealing the root from coming into contact with gas, in which case the root can still absorb DO, which may or may not be superior amounts of oxygen as opposed to medium based growing / hand watering without aeration.. does this make sense?

 

[Carboy]

I'm not saying this to pick a fight, argue or be an ass. But this thread must set some sort of record for the amount of misinformation. This has the potential to really screw up a beginner. Believe what you want, but it would help if you had some facts to base it on ...... not "I tried this once and look how good it did." For you that don't have your mind made up, the answers on O2 are here. Look thru this thread and pay particular attention to what Old Bubbler writes:
http://www.icmag.com/ic/showthread.php?t=124051

Of all the growing questions, research and physics solves the temp/02 issues. You can apply or ignore the results.

All the best ---------- CB

 

[lysol]

Actually that thread has misinfo, IMO.

"Aeration speeds up this process of oxidizing organic and mineral pollution. In fact, if there is sufficient aeration, the fish will be able to survive, where before they suddenly died. By pumping compressed air out to the bottom of a pond or lake with the use of a diffuser, the rising air bubbles and the friction caused in the water will bring bottom water to the surface where it is exposed to the atmosphere. Large volumes of water thus release noxious gases to the atmosphere, water picks up oxygen while circulating at the surface"

The question is not what causes aeration though, my question is can the plant's roots "breathe" or are they like fish gills and only use dissolved oxygen, and if the later what explains the fact a plant survives in wet soil

 

[Carboy]

Actually that thread has misinfo, IMO.

No misinfo from myself or Oldbubbler. You are correct on some others.

"Aeration speeds up this process of oxidizing organic and mineral pollution. In fact, if there is sufficient aeration, the fish will be able to survive, where before they suddenly died. The decomposing is producing nitrates and nitrites which robs the water of 02. This also makes a perfect environment for anaerobic bacteria -- the nasty shit we don't want. Aeration re-supplies the necessary O2 for fish and favorable plant life. By pumping compressed air out to the bottom of a pond or lake with the use of a diffuser, the rising air bubbles and the friction caused in the water will bring bottom water to the surface where it is exposed to the atmosphere. Large volumes of water thus release noxious gases to the atmosphere, water picks up oxygen while circulating at the surface" True to a point. Actually more DO is produced when the bubbles are contacting the water bubbling thru than while circulating on the top. Assuming small bubbles from diffuser.

The question is not what causes aeration though, my question is can the plant's roots "breathe" or are they like fish gills and only use dissolved oxygen, and if the later what explains the fact a plant survives in wet soil Plants use DO. That also explains why plants die in a continually saturated soil. I don't know if plants can take O2 w/ their roots directly from the air. Intuitively, I'd say no. A citation would over rule my intuition.

CB

 

[lysol]

If a soil plant could only use DO then when I let it dry out wouldn't I see symptoms of over watering ( from lack of oxygen )? What about soil growers who grow in 100F heat, surely there is very little / no dissolved oxygen capacity in the water at that point?

Could you give me a source for "bubbles add DO before hitting the surface, and its not surface agitation that does it"? Or are you just saying what seems to make sense? I think just because one guy says he used smaller bubbles and it improved yield does not conclude how aeration works, merely that smaller bubbles increased whatever causes dissolved oxygen ( surface agitation? )

 

[Carboy]

If a soil plant could only use DO then when I let it dry out wouldn't I see symptoms of over watering ( from lack of oxygen )?
Yes. For the purpose of what we are discussing: a plant in standing water and a plant in completely dried out soil is suffering from the same symptoms. More accurately: If the soil is maintained too wet for a substantial length of time, it will partially suffocate the microbial activity necessary for plant food conversion for plant uptake. Too long a dry period will result in a lack of moisture to support plant transpiration even though there is plenty of oxygen in the soil. ripped off from internet someplace
What about soil growers who grow in 100F heat, surely there is very little / no dissolved oxygen capacity in the water at that point?
I live where it is 100 (ok, ok, it was in the 90s today). Guess what the SOIL temp is at 12"? For the hell of it, i checked .... 70F -- give or take. No O2 problem there.
Could you give me a source for "bubbles add DO before hitting the surface, and its not surface agitation that does it"?
Glad to Mortimer, C.H. 1956. The oxygen content of air-saturated fresh waters, and aids in calculating percentage saturation. Intern. Assoc. Theoret. Appl. Commun. No 6.
Or are you just saying what seems to make sense? It does make sense, but you can read this APHA.1995. Standard methods for the examination of water and wastewater. Amer. Publ. Health Assoc.
Or if you are really interested, you can calculate it

So now that you have solved for Cp you can finally determine %saturation based on your DO concentration (mg/L) by going one more step:

Equation 3

You could do any of the above or the lazy ass way i did and talk to people that make commercial diffusers for a living and ask what the hell is going on.
I think just because one guy says he used smaller bubbles and it improved yield does not conclude how aeration works, merely that smaller bubbles increased whatever causes dissolved oxygen ( surface agitation? )
Believe me, there is no mystery how aeration works. or why it works. There are no opinions. There are facts and there is ignorance

These are the facts:
The larger the volume of air, the colder the water, the taller the water column, the finer the bubbles, the more dissolved oxygen up to 100% saturation.
Anybody tells you differently is wrong.

CB

ps The answer to the original question -- Do bubbles give o2 to the roots or just kill pathogens? Both -- good environment for what you want and hostile for what you don't.

 

[hoosierdaddy]

One thing is for certain...water that is sitting undisturbed will outgas all of the available DO in a matter of time. The same container will not uptake any oxygen at all just sitting there.
To think a res is going to gain DO simply by opening up holes to allow the res exposure to the atmosphere, is ridiculous.

And it is pretty well established that atomizing of the air tends to increase the amount of DO over what a large orifice of air can.

Introducing h2o2 can increase healthy DO levels like no air introduction device or method can possibly.

 

[Carboy]

One thing is for certain...water that is sitting undisturbed will outgas all of the available DO in a matter of time. The same container will not uptake any oxygen at all just sitting there.
To think a res is going to gain DO simply by opening up holes to allow the res exposure to the atmosphere, is ridiculous.

And it is pretty well established that atomizing of the air tends to increase the amount of DO over what a large orifice of air can.
I was cheering ya on until this last line. Not true
Introducing h2o2 can increase healthy DO levels like no air introduction device or method can possibly.

Look at this way. Say you add 5ml of 35% H202 / gal to 50 gal rez. You have added roughly a cup. Only 1/3 (35% solution) is active. Let's say 1/2 of the oxygen in the peroxide is available. Now we are down to 1/6 or less than 3 tablespoons of O. That's best case, figuring everything on the high side. Even assuming all the O is used --- that ain't very damn much. Plus how long do you think it will stay dissolved ? Not very.
The benefit of adding H202 is that the radical oxygen molecule will attach and oxidize pathogens (on the downside, it going to oxidize some good shit too). The benefit of oxygen in rez from H202 is so insignificant that i don't really understand why articles even mention it. Personally, i run a mild peroxide as a preventative once a week. W/ DO levels good and temp right, it is entirely unnecessary. I'd take the littlest pissant aquarium pump running an open tube over a case of H202.

CB

 

[hoosierdaddy]

Well, you can assert that my statement is not true, but then you bear the responsibility of proving it.
It IS true. And all one needs to do is research the subject and find that the introduction of h2o2 can increase the level of DO by maybe 10 times that of an airstone.

Btw..I have used h2o2 for years, and have several grows with and without. I know it is great stuff and has several benefits as both a preventative and corrective measure.

When you make statements using only you logic it shows. For one thing...h2o2 doesn't dissolve. All it does is react and becomes hydrogen and oxygen gasses, and liquid water.
And a correct dosage takes about 3-5 days (subjective to other variables) to dissipate from a clean res., and probably less in a soil medium, due to more reacting.