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RDWC actual Dissolved Oxygen test results are very impressive

JohnM

Member
Hydroponic experts and some hobby pot growers claim that oxygen (DO) is vitally important in RDWC pot grows. Most hobby growers and water chiller salesmen say that big air pumps, plenty air and cold res water (<70F) will absolutely insured plenty oxygen (DO), their proof is a copy of a DO Chart prediction.
An O2 concentrator totally eliminates noisy air pumps, water chillers and that constant worry about low DO, root suffocation, root rot and fungal infestations.
A reconditioned Oxygen Concentrator. The actual res water DO test results are really impressive… DO Saturation 120% - res water temp 82F.
I Googled “used medical oxygen concentrators for sale” and found many refurbished brand name oxygen concentrator with a 1 year warranty cost $200 - $300. An O2 concentrator cost is negotiable on E-bay, bidding starts around $35.00.
Many patients with advanced lung and heart diseases own oxygen concentrator and thousands of these patients die every day. Their families sell this O2 equipment ASAP after the funeral – try an ad in the Green Sheet or news paper, “want to buy used oxygen concentrator” You will find this O2 equipment to be inexpensive and the price is always negotiable because the family wants to get rid of this O2 equipment now that the patient is gone… < $50.00.
 

Douglas.Curtis

Autistic Diplomat in Training
Interesting information, thanks for sharing. From the perspective of someone with 15 years experience with DWC, RDWC is more expensive to build and run for the same results.

Airstones provide cooling (when the pumps have access to cool air) and turbulence which keeps the reservoir evenly mixed. They also seem to have provided sufficient DO to produce extremely impressive grows, for a few decades. It's also ridiculously inexpensive to set up and run.

I have yet to see anyone publish a full size DWC or RDWC grow, from start to finish, at 82F res temps. I admit I haven't read every grow show on the net, so if you know of one I'd appreciate you sharing the link. High (edit: biological activity levels) are much easier to create at 82F, my max is 70F for zero problems.

Good tips on finding O2 equipment, you're right on the money there. :)
:tiphat:
 

JohnM

Member
Interesting information, thanks for sharing. I admit I haven't read every grow show on the net, so if you know of one I'd appreciate you sharing the link. High DO levels are much easier to create at 82F, my max is 70F for zero problems.

Good tips on finding O2 equipment, you're right on the money there. :)
:tiphat:


You’re welcome. Just sharing a few facts that I have discovered.


Yes, after actually testing the DO with a YSI DO meter, I found that you are absolutely correct here.


Unnatural high DO levels do insure continuously safe oxygenation 24/7 for months using oxygen-enriched gas (>24% oxygen – 93% oxygen) generated with an inexpensive used medical oxygen concentrator and bubbled into the water and confirmed by DO testing with a DO meter.


It is extremely easy to supersaturate DO in reservoir water @ 82 F with an oxygen concentrator. Achieving 100% DO saturation is not possible to do with ambient air in a hydro grow containing mature plants and beneficial microbial colonies.


All DO chart prediction are based on ambient air, ambient air pressure, water salinity and water temperature… but those DO charts do not subtract DO consumed in the metabolic process nor the biological oxygen demand from all the aerobic plants and microbes from these DO chart predictions. Aerobic plants, roots, and microbes consume a considerable volume of dissolved oxygen every minute of the day and that DO consumption is not reflected by the DO Chart. More aerobes consume more DO in all Hydro-grows. That consumption must be subtracted from the DO chart prediction for a realistic prediction. And a DO chart prediction is very different than an actual DO test result using a meter or strip test.


Consider this:



  • 82 F water does not compromise nor retard root metabolism and growth nor does the warmer water retard beneficial microbial metabolism and growth compared to cold 65 F – 70 F water temps.. *Plants grow to maturity quicker when healthy, yearly bud production is greater and plants and microbes are healthier.
  • Maintaining continuous DO Super-saturation (> 100% Do Saturation) inhibits insures NO low O2 crisis, NO fungal colonization and healthier plants and rhizome mass. You need not even think about nor worry about root rot and fungal infestations and brewing teas any more.
  • Eliminates all possibility of low oxygen problems, root suffocation, root rot or fungal outbreaks throughout months of the growing season.
  • Root suffocation is deadly and caused by an irresponsible grower that fails to tend to his hydroponic life support system.
  • The fungi do not the cause of the roots dying, rotting and decaying, fungi simple eat the dead mess, no different than a gang of buzzards eating road kill.



As much as you have scrubbed the internet over the last decade or 2, I seriously doubt that you would ever see grow videos or pics originating from a state where using and cultivating pot is illegal and routinely prosecuted.


Thanks for sharing Doug.
 

Douglas.Curtis

Autistic Diplomat in Training
As much as you have scrubbed the internet over the last decade or 2, I seriously doubt that you would ever see grow videos or pics originating from a state where using and cultivating pot is illegal and routinely prosecuted.
Really? You must have missed the last 2 decades of the internet. Almost all, up until the last few years, of my online research has included videos and pictures from illegal states. (You HAVE read the forum you're posting on... right?)

Where are the grow shows? Show me why I should be paying more electricity for 02 in my reservoir? (I'm currently using 12 watts) I would like to see 82F reservoir temps, all the way through harvest. Heck, show me a couple grows and I won't mind a bit.

:)
 

PetFlora

Well-known member
ICMag Donor
Veteran
Do you run this on a timer? Doesn't seem like it needs to be on 24/7

I run my rez aerating pump 4/30 24/7
 

JohnM

Member
Really?

Where are the grow shows? Show me why I should be paying more electricity for 02 in my reservoir? (I'm currently using 12 watts) I would like to see 82F reservoir temps, all the way through harvest. Heck, show me a couple grows and I won't mind a bit.

:)
Yes, Really! Like I said, “I seriously doubt that you would ever see grow videos or pics originating from a state where using and cultivating pot is illegal…”
I have seen U-tube videos of real time crimes posted on the internet, TV News and TV documentaries. What kind of individual would commit a crime, video the crime and publish the crime video on the internet? A special individual for sure.
I will definitely give you a triple +++ for your friendly persuasion today. Anyway, the answer is still NO, NO pics, NO videos, NOT until state cannabis cultivation and use laws change and I am absolutely sure that will NOT be today or tomorrow.
I do like the way you bait the ego for production. I remember this classic ploy presented in a sociology class years ago which in many cases will and does produce results.
I understand, your electrical budget is seriously limited to only 12 watts and that cool, that’s your choice.
 

Douglas.Curtis

Autistic Diplomat in Training
Oh, I see. Nothing from you, because you live in an illegal state. No worries. I'm stating I've yet to see it anywhere period, that's all. Plenty of other people have posted their illegal (and now legal) grows for decades. So... you're here to share in text and what you have is unique, without outside peer corroboration. Got it. Nothing against your position, looking forward to you achieving what you're after.

As for my resource consumption, I grow for quality and efficiency. :tiphat:
 

gh0stm0de

Active member
There is a direct relationship between water temperatures and DO ceiling. As water is hotter it can hold less DO. Therefore it is easier to maintain saturation level at higher temps because it requires less DO.

North of 70 is pythium and root rot territory. I have grown with and without a chiller and would not do so without again. Even in cold temperatures, water temperature regulation is key as 65 and under can begin to cause lockout and nutrient accessibility issues.

Although DWC is overwhelmingly my favorite system, there is a right tool for every job and if you arent going to take advantage of the level of control you have to optimize your medium, you are likely better off watering fox farm. Just my .02
 

delta9nxs

No Jive Productions
Veteran
i use no chiller. my reservoir temps are 79-82f all the time. i don't aerate. i don't use high speed water movement.

but i'm also not in dwc or rwdc anymore so for you guys still going that way try a "speece" cone.

a speece cone injects pure o2 into a stream of moving water. this will temporarily raise the do levels. i say temporarily because o2 depletion begins the moment you stop.

https://www.youtube.com/watch?v=LEeS_IxxH4M

this just shows one at work. you can see the bubbles disappearing before they reach the bottom of the cone indicating they have been dissolved.

o2 is injected at the top of the cone along with a stream of water that is matched to the o2 injection rate in such a way as to cause all the bubbles to be absorbed before they can reach the bottom. only the supersaturated water leaves the cone, no bubbles.

these things have been built on a massive scale for waste water treatment.
 

PetFlora

Well-known member
ICMag Donor
Veteran
Let's all put on our DIY hats

Air pump can be used to pump air though tubing into a vessel filled (and being constantly replenished) with nutrients. Enriched nutes can be 'skimmed/siphoned' off and returned to the rez

This way there is no messy or clogged stones

Thoughts?
 

Douglas.Curtis

Autistic Diplomat in Training
i use no chiller. my reservoir temps are 79-82f all the time. i don't aerate. i don't use high speed water movement.
You're running roots-out systems now, which do great in higher heat levels. :)

I am (for flower) exclusively DWC. I have grown without a chiller for 15+ years and my res temps are always 67-68F. (Hang your air pump(s) in 65F air) The only water movement is from the quality airstones, replaced every cycle or two to remove worries of clogging. Cheap insurance. ;)

I'm interested in seeing results which would make me go looking for an O2 machine. I'll step out of the way and let progress take place. :tiphat:
 

JohnM

Member
i use no chiller. my reservoir temps are 79-82f all the time. i don't aerate. i don't use high speed water movement.

but i'm also not in dwc or rwdc anymore so for you guys still going that way try a "speece" cone.

a speece cone injects pure o2 into a stream of moving water. this will temporarily raise the do levels. i say temporarily because o2 depletion begins the moment you stop.

https://www.youtube.com/watch?v=LEeS_IxxH4M

this just shows one at work. you can see the bubbles disappearing before they reach the bottom of the cone indicating they have been dissolved.

o2 is injected at the top of the cone along with a stream of water that is matched to the o2 injection rate in such a way as to cause all the bubbles to be absorbed before they can reach the bottom. only the supersaturated water leaves the cone, no bubbles.

these things have been built on a massive scale for waste water treatment.
Delta presents very interesting oxygenation technology that’s out of the box so to speak for the average hobby grower, thanks for joining my thread delta. I appreciate your comments.
Cones are a neat way to dissolve O2 gas to supersaturation levels into warm water fast and efficiently. Totally eliminates and all Low DO problems, root suffocation, fungal outbreaks, all gone forever. Cones dissolve much more O2 gas far better than water chillers, water falls, hypothermia and 100 bubbles stones running continuously bubbling tons of ambient air.
Do you have any pics or videos of this thing used in a grow? Doug will want to see pics and videos… that is the proof that cones really increase the DO to high supersaturation levels… just kidding Doug, playing around.
Of course a DO meter is necessary to actually prove the effectiveness of any cone, bubble stone, water fall or air pump.
 

JohnM

Member
You're running roots-out systems now, which do great in higher heat levels. :)

I am (for flower) exclusively DWC. I have grown without a chiller for 15+ years and my res temps are always 67-68F. (Hang your air pump(s) in 65F air) The only water movement is from the quality airstones, replaced every cycle or two to remove worries of clogging. Cheap insurance. ;)

I'm interested in seeing results which would make me go looking for an O2 machine. I'll step out of the way and let progress take place. :tiphat:
Doug, what altitude do you grow DWC pot? Just wondering. Thanks
 

delta9nxs

No Jive Productions
Veteran
Delta presents very interesting oxygenation technology that’s out of the box so to speak for the average hobby grower, thanks for joining my thread delta. I appreciate your comments.
Cones are a neat way to dissolve O2 gas to supersaturation levels into warm water fast and efficiently. Totally eliminates and all Low DO problems, root suffocation, fungal outbreaks, all gone forever. Cones dissolve much more O2 gas far better than water chillers, water falls, hypothermia and 100 bubbles stones running continuously bubbling tons of ambient air.
Do you have any pics or videos of this thing used in a grow? Doug will want to see pics and videos… that is the proof that cones really increase the DO to high supersaturation levels… just kidding Doug, playing around.
Of course a DO meter is necessary to actually prove the effectiveness of any cone, bubble stone, water fall or air pump.

no, i've never used one in a grow and don't know of anyone who has but 10 years ago, when i was running bio-buckets, i was going to build one and actually got to the drawing and parts stage before i changed techniques.

i think it would be quite simple to build a small one out of maybe a small traffic cone with some pvc fittings at the top. maybe a gas injection jet of some kind. i think you establish water flow first then dial in o2 flow rate so that no bubbles are emerging from the bottom of the cone.

adequate plant o2 is adequate o2 and no more is needed nor will excess o2 "turbocharge" a plant.

the trick in dwc is to not let the bio-demand for o2 deplete the do much past what the water would normally hold under whatever ambient conditions you have. so going for "max" dissolved o2 levels is not going to get you any further than adequate do levels.

but no water at any saturation level can compete with ambient air when it comes to plant available o2.

two containers the same size, one filled with water with o2 content dictated by atmosheric partial pressure, and the other filled with ambient air at the same altitude and temperature.

the container of air will have approximately 23,300 times the free o2 molecules.
 

JohnM

Member
I've had multiple grows at every altitude I've lived at. From 1,300ft to just below the tree line in the Rocky Mountains. ;)
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.
At the tree line in Colorado, 11,000 ft. elevation, you have lost 32% of the available O2 found in ambient air at sea level. Believe it or not, 32% loss of O2 is a substantial compromise when it comes to metabolic efficiency and health.
Ambient air at sea level and at 11,000 ft. elevation in Colorado contains about 21% O2. A candle flame requires an oxygen level of greater than 18.8% or 131.6 mm/hg partial pressure of O2 oxygen at sea level to remain alight. At 1300 ft. elevation, you have lost 4% of the available O2 in ambient air that is available at sea level. Insuring enough O2 to sustain optimal metabolism is not as simple as it appears at a glance upon further investigation.
I believe you will be shocked in the difference in plant health using oxygen enrichment techniques at altitude compared to air pumps and plenty flowing water running through your DWC life support system. But on the other hand, why would anyone change old habits and ideas and live with the old ways.
Actually, a losing 32% of the available O2 at the tree line elevations causes a substantial metabolic compromise. You might want to rethink just how much is your crop really compromised at altitude growing because of that 32% loss of O2.
Better yet, you might want to do the math and see for yourself just how compromised DWC growing can be at various altitudes, go ahead and check it out - Altitude air pressure calculator http://www.altitude.org/air_pressure.php
Let’s apply 2 chemistry gas laws to skin this cat; Boyle’s Law about O2 gas partial pressure at different altitudes and Henry’s Law, the partial pressure of O2 required for saturating and supersaturating O2 into water. O2 does not dissolve easily into water at sea level and dissolved much worse at every foot of elevation.
By the way, if you like to bet on stuff at bars with the local heads and want to make a few easy bucks… you can bet your car keys, wife, kids, girlfriend that altitude directly compromises aerobic plant and microbial metabolism every foot of altitude. Actually that bet no gamble at all, that’s like having a Royal Straight Flush in a 5 card stud poker game. You are going to win that game because it is solidly based in science, elementary Chemistry and Physiology 101.
Manipulating O2 gas concentration and manipulating metabolism with O2 is interesting. You can’t cut iron and steel with ambient air, you got to have pure O2 and acetylene make fire hot enough to do that.
Have you seen healthy pro football players breathing pure O2 on the bench with an O2 mask in Colorado to boost their compromised metabolism --- I believe it’s same deal with the pure O2 at altitude.
 

PetFlora

Well-known member
ICMag Donor
Veteran
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?
 

mushroombrew

Active member
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?
 
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