I have a Dissolved Oxygen meter

[clowntown]

I doubt it'd make much of a difference... one type of system (no stone) is generating more DO.

But if possible, something in the mid- to high-60's? Something in the ideal operating temperatures.

Also, how about a container with some solid mass to break up the bubbles from the open airline, to simulate the root mass from a DWC bucket for example. This way, the large bubbles aren't going as wild at the surface as it would in a plain water container.

 

[Guest]

I did do some testing, about 3 hours worth. I guess Im not patient or dont have enough free time to accomplish all you guys ask.

Anything you can do will be helpful and appreciated. First I'd think that the action of dispensing tap water, especially at that temp, will force in a lot of oxygen. I'm guess it would need to sit for an extended period but only way to tell is measure out of the tap and after a day or so in a bucket. It'd be great if you could report the actual readings.

I wonder how much air is moving through the open line compared to through the resistance of a stone? Still...interesting DO only went up with the open line. I agree with Clowntown that temp shouldn't make a dif.

As for what else...let the water sit for a bit, especially in something like the test where DO went up, after turning off the air and test.

 

[Dr.greenlove]

and...... are we 100% positive that the highest DO is really the ultimate goal?

maybe total usable O to the root mass is something to explore, no?

 

[clowntown]

Isn't dissolved oxygen usable oxygen, at least in DWC?

 

[Δ9-THC]

Yes, but that doesn't mean 100% DO will benefit you over say 87%.. I think that's Dr.greenlove's question? This is a botany question that I don't know the answer to.

 

[clowntown]

Water can only hold so much DO. I forgot the exact numbers but it's very low in comparison to what can be held in non-water mediums, such as good soil or soilless. So even if you're able to saturate the water with as much DO as it can hold via aeration, it will still be lower.

 

[guineapig]

OMG morgan let's get together (drool).....i am a dissolved oxygen freak with continual supplies of medical grade O2....

Now try to get your hands on some bottled Oxygen, would be my suggestion....then, once you have it, try to force as much oxygen as you can through a very small plastic tube, and then record the Oxygen ppm of the water.....we can only lower the temperature of the water to a certain point, after which the roots go into cold shock, but experiments with injecting massive amounts of dissolved oxygen into a given source of water via high-pressure do seem promising.....

it all comes back to the ideal gas equation:

PV = nRT

(Pressure) x (Volume of water reservoir) = (moles Oxygen) x (universal gas constant) x (Temperature)

This equation explains why as we lower the temperature of water, the amount of dissolved Oxygen gas (represented by moles Oxygen) increases.....it also explains
why as we increase the pressure of a given volume of water, the amount of dissolved
Oxygen gas also increases.......

My Dissolved Oxygen thread is around here somewhere......

your pal guineapig

 

[Guest]

and...... are we 100% positive that the highest DO is really the ultimate goal?

maybe total usable O to the root mass is something to explore, no?

That's my goal...to achieve DO saturation in my nute solution and why not? I've come across a few formal studies on the net and high DO levels are critical for healthy plants and proper growth. I wish there was more hard data forthcoming in this thread.

This visual kit from CHEMetrics seems like the best low budget test kit available to test DO. I hate visual test methods like this but the next step up is like $300+ for a decent DO meter for most likely a one time goround logging data. It should be pretty easy to test my nice new air stones and pump against straight air pumping through the lines. I can test a few other variables as well in my setup for only $45 + shipping .

EDIT - CHEMetrics #K-7512

 

[BlindDate]

I haven't heard anyone talk about "air roots". Does a plant use these? If so, oxygenating the water is not nessessary as long as an air gap exists between the root ball and the reservoir.

Has anyone done a comparison using a progressively increasing air gap?

 

[mace_ecam]

BlindDate, what are "air roots"?

 

[Sauce]

In a system like DWC the air space between the water level and the plant stalk. Roots that are not submerged in water should be constantly taking up o2. So his question is how much does this air gap matter in getting plentiful amounts of o2 to the roots.

It would be an interesting experiment that wouldn't rely on DO meter readings that much.

 

[vhGhost]

i forget where i read it(maybe 3LB threads).. but i believe that it covered the info about what different parts of the roots do.. like - the top part of the roots are where the plant will intake food+oxygen , and the the bottum part will look for water.... i hope someone can confirm this ... i'm looking for the thread right now!

 

[clowntown]

I haven't heard anyone talk about "air roots". Does a plant use these? If so, oxygenating the water is not nessessary as long as an air gap exists between the root ball and the reservoir.

Oxygenating the water would still be necessary to control pathogen population in the reservoir and keep things healthy, no?

 

[Sauce]

Yes that's true but I think what he means is maybe getting o2 levels up a lot with a big pump may not matter if there are a lot of air roots taking in o2. Maybe a small pump would suffice fine. Not saying this is true or not, but it would be an interesting experiment.

 

[mace_ecam]

as far as i'm concerned, the plant takes care of what kind of roots its gonna grow, depending on the environment

whats the toxicity level for DO?

 

[Sauce]

whats the toxicity level for DO?

I don't think there is one since max DO levels are extremely low. You couldn't get 10ppm DO without supersaturating the water and I'm not even sure how you would do that or if it's possible.

 

[mace_ecam]

Yes sauce, with ordinary air (partial pressure law) at normal temps & pressure there is no way in the world to go over 8ppm DO, which is far from toxic.
However, i remember a post on OG where a guy used an medical oxygen concentrator to pump nearly pure O2 in the water, he reported of a toxity if he pumped to much O2 in there, but he didn't have an DO meter.
So i thought i'll ask here, maybe someone has both...

 

[gmanwho]

On the toxicity thing. When i was searching arround for oxygen levels in normal air, i ran across a study. They study showed in HUMANS, prolonged exsporsures to 87% or higher oxygen did something like slowed cell regeneration. Not 100% on that, so dont quote me. But I will try to find the article.


b-safe

 

[mace_ecam]

dude, 87% is definately toxic to humans, apart from that, it would turn all your clothes into something extremly flamable.

 

[clowntown]

Clothes? Forget clothes. The entire room would be flammable. Better not spark that bowl, or you could be dead if you're in a room of 87% oxygen.