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RDWC actual Dissolved Oxygen test results are very impressive

PetFlora

Well-known member
ICMag Donor
Veteran
So you are basically injecting air richer in O2 into your system?

Have you used venturi valves/injectors? I have injected bottled O2 into a system with great success.

I am all for increasing O2. But I would never run @ 82F. Trust me if you get Fusarium wilt you will never run in the 80's again. "The slaughter" I call it.

Very much strain/pheno dependant. I have one pheno that will not tolerate 76-78F. Roots must have higher O2 demand than others. They start yellowing at 75.

I hit 70's when I have equipment faliure. Othewise it's 62-65 and O2 rich. Even 55F in winter which I love. I run open reservoirs in my cold air mixing room. I use about 3 times as much air as most. As such enrichment is attractive.

What is the O2 partial pressure being generated? Meaning how much higher than atmospheric?

Do you have any grow threads? I am also thinking to inject pure O2, but it still needs metering, no?
 

JohnM

Member
delta9nxs;8132763 adequate plant o2 is adequate o2 and no more is needed .[/quote said:
And let’s not leave out the additional O2 required by all the aerobic microbes as the colonies grow for months.
Not trying to aggravate you or increase your blood pressure, but exactly what do you really mean when you say “adequate O2?” Will you please be more clear?
What does “adequate O2” (DO saturation) literally mean to you? Does adequate DO saturation mean optimal safe DO that is required 24/7 continuously for the duration, months of the growing season?
To me when I hear “adequate O2” that does not mean the optimal DO, the safest continuous DO saturation possible. “
Actually testing the reservoir water with a DO meter or chemical titration test, does “adequate O2” mean 25% DO sat, 50% DO sat, 75% DO sat or 100% DO sat or maybe 135% DO sat depending on the biological oxygen demand of a mature crop containing all the aerobes living in that reservoir water. More aerobes require more available O2 continuously.
Interesting subject, adequate or plenty... how much O2 gas is required to really thrive.
 

mushroombrew

Active member
Veteran
Do you have any grow threads? I am also thinking to inject pure O2, but it still needs metering, no?

No grow threads on that sorry. I was running Reef Aquaria back then and injecting CO2. I used the injection setup on my RDWC. And used Welding gas which is much cheaper.

You really cannot add too much. Water temp controls saturation. And Altitude too as mentioned before.

Basically you need a tank, regulator, tubing and a small venturi valve. No idea why they can it a valve it is an injector imo.

https://www.kentmarine.com/products/venturi-valves.htm

Ideally you will see no bubbles coming out return line. Meaning it is all dissolved into the nute solution. So adjust flow accordingly.
 

Douglas.Curtis

Autistic Diplomat in Training
The lower partial pressure of O2 in ambient air at altitude, the greater the metabolic compromises for aerobic plants and microbes, general health and growth.
There are many serious metabolic issues caused directly as a result of low O2 problems and suffocation in DWC growing at altitudes. DWC growing at sea level is basically care free and easy provided the grower does not suffocate the crop.
Yep, and 12 watts of airpump power, (4)3$ airstones and $10 worth of airline tubing does the job beautifully, for 45 gallons. Doesn't matter what the altitude is, the results are the same. :tiphat: Keep going though, it's interesting watching people work together. ;)
 

mushroombrew

Active member
Veteran
Lower air pressure reduces the solubility of oxygen in water so I believe it does matter.

Maybe more pertinent to fish in a lake vs. a hydro system with aeration?
 

JohnM

Member
So, I've been thinking and searching YT for DO generators

Cheapest I've seen that looks like it will work: cost $175, but how to measure the effect?

I googled Dissolved Oxygen Meters finding they range from ~ $150>

https://www.amazon.com/Milwaukee-Ec...rd_wg=mHcND&psc=1&refRID=VKB776K5EJR5TPHQNGAS

Are they worth it? I already have a 4 outlet air pump (used in my baby crib to start seedlings/clones), which may or may not provide more DO than what I am currently using in my grow room rez, a 260 gph lp side flow pump (water exits down low on one side). I have a venturi attached to the top exit, significantly enhancing DO. This set up is on a deep cycle timer 4 minutes on/ 30 minutes off. I do rotate blue ice packs, but quite often rez temp exceeds 74*s. I'm thinking the place to start (for me) is a DO meter, then I can more accurately dial in the pump o/o times. Anybody?

Assuming controlling DO raises final weight by as little as 5 grams/plant, even with one plant over 3 grows pretty much pays for it.

Anybody know of cheaper DO meters?
Tools and calculations…
How to measure the barometric pressure - a barometer
How to calculate the partial pressure of O2The gas partial is the individual gas pressure exerted independently by a particular gas within a mixture of gasses in ambient air. In ambient air the primary gases in the mixture are Nitrogen 80% and Oxygen (O2) 21% ... So, given that total atmospheric pressure (at sea level) is about 760 mm Hg and, further, that air is about 21% oxygen, then the partial pressure of oxygen in the air is 0.21 times 760 mm Hg (sea level barometric pressure) or 160 mm Hg. The barometric pressure decreases as altitude increases above sea level.
How to measure the dissolved oxygen (DO) in water – a DO Meter
HERE’S CHEAP $0.50 PER TEST - Dissolved O2 in water may also be measured - Salifert Dissolved Oxygen Test Kit – $22.31/50 DO test + FREE SHIPPING -- https://www.amazon.com/Salifert-Dissolved-Oxygen-Test-Kit/dp/B001EJ3DQ4
How to predict the Dissolved Oxygen (DO in fresh water containing no plants, no animals and no microbes in that water consuming NO oxygen) basically water containing NO living aerobic plants or organisms – an internet DO chart and a thermometer to measure water temperature.
But what is the point of the exercise????????
What is the point of DO testing, discovering that the DO IS low watching the roots suffocate?
What DO test results proves Low dissolved oxygen beyond any doubt?
How do you correct a low DO problem before the roots suffocate, die, decay and rot?
So what if you must deal with the root rot from time to time, that’s just part of DWC pot farming, replant and move on to new horizons. It’s no big deal for most growers.
 

LostTribe

Well-known member
Premium user
RWDC/DWC/SWC are all inferior to most other forms of hydroponics. You will never attain anywhere near the amount of oxygen as with the use of aero. I prefer hydroton to keep more moisture. The roots must breath. You are soaking them and basically choking them out. I've run it and definitely done with it. If you think I am wrong do yourself a favor, I will now direct you to the ICmag is Boring as Shit thread.

SoQuick wherever you at Respect!
949IMG_1096.JPG

949IMG_1098.jpg

949IMG_1099.JPG


The ICmag is boring as shit thread
https://www.icmag.com/forum/marijuana-growing/indoor-grows-hydro/4665-ic-is-boring-as-shit/page5
 

PetFlora

Well-known member
ICMag Donor
Veteran
I stopped growing after my green thumb turned black over a year ago. Couldn't get seedlings past 3rd node, but here is a couple pictures from simple F & D
 

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hyposomniac

Active member
RWDC/DWC/SWC are all inferior to most other forms of hydroponics. You will never attain anywhere near the amount of oxygen as with the use of aero. I prefer hydroton to keep more moisture. The roots must breath. You are soaking them and basically choking them out. I've run it and definitely done with it. If you think I am wrong do yourself a favor, I will now direct you to the ICmag is Boring as Shit thread.

SoQuick wherever you at Respect!
949IMG_1096.JPG


949IMG_1099.JPG


The ICmag is boring as shit thread
https://www.icmag.com/forum/marijuana-growing/indoor-grows-hydro/4665-ic-is-boring-as-shit/page5

That thread makes me question every decision I've made
 
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