Aeroponic Experiment

[Blazer420]

I have been thinking (too much) lately about some interesting (to me) ideas of how I could experiment with my aero setup. I keep coming back to a keystone element in the traditional aero system - the oxygenation of the roots through air stones.

I am already using CO2 supplementation and that has been a great addition.

So why not consider similar supplementation but from the other direction.

I fill my own & friends SCUBA tanks and can blend just about any gas mixture needed for technical SCUBA, so I have a minimum of 6, 200 lb bottles of O2 on had at any time in my fill bank.

So, the idea came to me that I could easily increase the O2 content of the air the air pumps use to just about anything I want up to 100% O2 from its standard 20.9%.

In SCUBA we do it all the time. In fact, for years now, I will not dive shallow (less than 110') with anything less than 32% O2. The reasons for that are outside the scope of this post.

I have been trying to find some research on higher concentrations of O2 on plant roots, but have come up short on anything that speaks to levels higher than 21%. So I'm stuck thinking about how much of a good thing is too much. Am I going to oxidize the roots or the nutes? How my additional O2 can I add before this happens - if at all? Can the roots take up the extra O2 in the same manner the plant can with CO2? Will I throw off PH? Will the added O2 change the optimal PH range? WIll added O2 allow for more nutes to be absorbed? Will it compliment CO2? The list of questions goes on and on.

I guess the basic question here is what am I trying to accomplish? The truth is I have no idea. I guess I am just interested in seeing what might happen.

I would really appreciate any input.

Thanks!

B-

 

[Blazer420]

OK, things are getting a little more interesting as I dig into this.

I spoke with horticulturalist that teaches at the ag department of the local community college. Before I get into what he said, I want to state that I have not researched his comments so I am currently taking him at face value.

He explained to me that with an aero system that not only are we super oxygenating the water, we are also doing the same with all the other elements in air, which is mostly N. It was his belief that the accelerated growth of our plants had to do with both increased levels of N and O2 with N being a smaller molecule than O2 it is more easily absorbed into the root system than O2. He continued that if I were to increase the levels of O2 in the water, I would probably need to compensate with a similar increase of N through nutes (when I blend the gas, the larger quantity of N is being replaced by the higher O2 concentration - hence making is somewhat safer for SCUBA but again not germain to this topic). He finished by pointing me in the direction of some literature that should help out my research.

In the meantime I have begun to think about a design for the O2 enriched delivery system. I think that to stay true to KISS, I am going to run a tank of 32% NITROX (32% O2) through a solenoid and hook that up to a timer, and then plug my regular air pump into another timer with both connected to "T's" in the airlines. Then I am going to cycle between the two giving 30 min to each. To keep things equal I will run the NITROX at the same CFM flow rate as my air pump.

I am not going to change my current nute recipe (the standard Technaflora recipe).

Then I am going to sit back and wait to see what happens.

I was thinking that if I do it this way I have one control - my nutes. The rest will be simple observation. I'm also cycling the NITROX because it is still an unknown and if things go to hell, I may be able to reverse or correct any damage, and I am not hitting the roots with a huge increase in O2, but hopefully enough to see something.

Thoughts?

B-

 

[TorturedSoul]

Water only holds so much DO at a given temperature. You can supersaturate it if you like, but the excess will be more-or-less transient in nature - bubbles rise, break at the surface interface (seems like that in itself is a main oxygenating process for the reservoir), and most of the oxygen enters the atmosphere instead of staying in the reservoir.

I doubt you'll see a problem. I don't see any cause for worry about oxidation - it's not like you're wanting to use ozone.

I could, of course, be wrong. I always felt that the more DO I provided, the better the plants did. I was just using "the standard atmospheric mix," however.

Sounds like a worthy experiment.

 

[Blazer420]

Thanks for the response.

You are right, DO is temperature and salinity dependent. Warm slaty water will hold less O2 than cold fresh water. This is one of the main reasons that shipwrecks in the Great Lakes have remained intact mof a few hundred years.

So to get more DO I will need to lower the water temp. Also I am going to head over to the aquarium supply shop and get a salinity meter and/or specific gravity meter to see where that is at. Since the nutes in question are at some level salt based this will also come into play.

One interesting thing here is that O2 is depleted as organic material decomposes. So as root material, etc sluffs off it will reduce the DO - but how much is unknown in this case.

B-

 

[FrankFoster]

It is an interesting idea, on the side of maximum input. Its obvious that the better the air stone and the amount of little bubbles in the reservoir and in the individual setups, the faster the plants seem to go. But using just outside air, say three air stones per bucket, would almost certainly be more than enough to saturate the same amount and you don't run the risk of some type of acid response from the plants roots because the whole plant is existing in the outside atmosphere.

I have researched it a bit and there is a tipping point wherein the roots get disrupted by the bubbles and don't microscopically grow roots in that fine almost hairlike delicate end structure. You can use fungals to get a water dwc root system so fine and wispy that changing the water roughly will damage the structures. You also gotta watch the use of mycorozone and other substances for fungal growth on plants undersides if you are a newcomer to the science.

Root structures have been known grown in a restricted 5 gallon bucket on a plant 10 ft high and the plant can absorb 1-2 gallons of water in full sun per hour. So there are definite benefits to keeping a mild still water base with the spattering of o2 and ppm never more than 800. Evening out a chemical spectrum with buffered nutes including polymers in dwc can get you 400 ppm basically tap water with 250 ppm of the right mixes, and the whole plant is fed, no deficiency, no problems, huge buds. Could have gone to 1100 ppm but why, so the roots get salted and dont grow into what reminds me of the inside Rhine of a grapefruit. You want the grapefruit Rhine root system, microscopic feelers that suck in water scary.

Fungus symbiosis and a bit of bubbled water, with still periods like 1010101010101 constant half hours or even longer.

 

[Blazer420]

I think that there should be a way to rig this thread so that any reader listens to Don Ho's "Tiny Bubbles."

B-