How many bubbles for a DWC?

Ok thanks, I get it.

I'm with you illegal smile, there has to be a point of diminishing returns. I've scene that water is most saturated at 65 degrees. Even if you have the water 100% saturated, at what efficiency are the plants absorbing this and is it really necessary?

Earlymorninghigh said:

I'm with you illegal smile, there has to be a point of diminishing returns. I've scene that water is most saturated at 65 degrees. Even if you have the water 100% saturated, at what efficiency are the plants absorbing this and is it really necessary?

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I don't think anyone knows the answer or the points of diminishing returns for nutes, lights, heat and lots of other variables. They should use some stimulus money and research this stuff. Enquiring minds want to know!

In any process where one considers first limiting factors one should always look at which is the first or most common limiting factor to a system. In a chemical reaction you would determine which chemical would run out first and therefore stop anymore complete reactions. Here you would look at which would run out first but you look at it a little differently. First if you supply as much light as is tolerable to the plants without burning them then obviously that is not a first limiting factor as long as the lights are working. Secondly if you use an EC near the top end of what they plants can use without over fertilizing then that is not going to be a first limiting factor. This means your left with water DO. Water DO is the first limiting factor. Oxygen for roots is the first limiting factors in almost any system where the oxygen is delivered by DO as water holds only minuscule amounts of oxygen.

Water at cool temperatures only holds about 9 ppm of oxygen where at any commonly lived altitude oxygen makes up at least 20% of the air therefore 200,000 ppm of oxygen. Even to match growth comparable to a soil growth in some fairly poor draining soil a DWC system requires air stones or a good reservoir pump circulation system, or something to keep its DO high enough as the normal amount of DO in a reservoir of still water would drop to near zero quickly. To actually better the growth of a soil grow in poorly draining soil a DWC system would need its water to be over saturated with oxygen at all times. The fact that hydroponic grows such as an g aero grow in large tubes and standard hydroponic in very well draining media, or a ebb and flow in very well draining media will out grow a DWC even with water that is over saturated with DO is a perfect indicator that with a DWC system or a NTF system or a small tube aero stem DO is the most common first limiting factor. It is easy to provide adequate light, it is easy to provide adequate nutrients but it is impossible to provide enough oxygen to the roots through DO to prevent it from being the most common first limiting factor.

Diminishing returns when it comes to growing are much harder to determine as all variables are interconnected. If you change on then the diminishing return for all others will change. With ant system the diminishing returns would be at first based upon the first limiting factor. So for DWC everything would be first based upon how much growth can you receive if an overabundance of everything but DO is provided. Then base how much you can lower everything but the DO without decreasing growth. Then determine if you lower things a little more is the money saved less than the cost of the decreased production.

Calculating these things when there are so many variables and so many strains of plants would likely never be tried by a researcher or team of researchers. With mj being such a high dollar product most people just try to shoot for the maximum that their plants will tolerate without much thought as to the cost as all the inputs are cheap in comparison to the finished products value.

If you just wondering about the diminishing return as far as DO. Just pick a system that provides the most small bubbles the cheapest or that provided the most water turbulence at the surface cheapest if your reservoir has lots of open water surface. Turbulent surface water adds more DO to the water than bubbles, however there is usually not much open water surface once the plants start growing therefore from that point on small bubbles provide the highest water DO.

With a system using chemical fertilizers it is very doubtful you can ever supply to many bubbles. With organic fertilizers there are a lot of oils and these stick to the bubbles outer surface and a bubble layer starts accumulating at the waters surface. With a lot of bubbles the layer can grow thick ck enough to overflow the top of the reservoir. This what Protein Skimmers use a pump that provides huge amounts of small bubbles. They are trying to remove the organic oils so they purposely inject enough small bubbles to over flow that layer of oil covered bubbles in what they call a protein skimmer.

Thanks again Fatman.

The point of what I'm doing isn't really just to improve on the performance of DWC or anything like that necessarily, that would be nice but that's not what it's about It's to simplify, reduce costs, and make maintenance easier long term on large scale RDWC ops that's the real point.

They have become quite complex and yes like you said nobody trims the fat because what works has always worked and overhead is paid for by the pot anway. Nobody else really sees the point in all the effort to work out the kinks in changing it or doing anything vastly different. If nothing more I learn things and I'm not out stabbing old ladies and stealing their purses.

If you want to see a needle wheel pump that will keep a huge, huge reservoirs water over saturated with DO just look at a Reeflo Orca needle wheel. Where there is a will there is usually a way. With a small air pump pushing air into the venturi this pump would work on a 500 hundred gallon reservoir easily.

http://www.aquacave.com/detail.aspx?ID=1348

This is the skimmer it usually powers: http://www.aquacave.com/reeflo-orca-pro-2-br-recirculating-protein-br-skimmer-2633.html

Great idea Fatman, I was looking at that pump yesterday... We are on the same page.

Earlymorninghigh said:

I'm with you illegal smile, there has to be a point of diminishing returns. I've scene that water is most saturated at 65 degrees. Even if you have the water 100% saturated, at what efficiency are the plants absorbing this and is it really necessary?

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Woo dude.

Consider this:

At different tempeatures 100% saturation is a different level of DO. True. Then also consider water that is aerated or very turbulent can cause super saturation of water with oxygen. WOW! This can be done whether the water is warm or colder. It is simply easier when it is colder.

People drag up data tables like that below but this is data for when there is no aeration or turbulence but merely lightly circulating water as in a calm ocean, river or lake. The only true way to see what is going on in your resrvoir is to take DO readings.

These are the levels of 100% saturation at different temperature if no DO is being used and all things are at equilibrium.

*32 degrees = 14.60 ppm 160 % of 68 degree DO
*45 degrees = 12.13 ppm 134% of 68 degree DO

A bit more reasonable temps:

*59 degrees = 10.07 ppm
*64 degrees = 9.45 ppm 93.8 % of 59 degree DO
*68 degrees = 9.08 ppm 90.01 % of 59 degree DO
*73 degrees = 8.56 ppm 94.27 % of 68 degree DO
*77 degrees = 8.24 ppm 90.75 % of 68 degree DO
*81 degrees = 7.95 ppm 87.56 % of 68 degree DO
*84 degrees = 7.67 ppm 84.47 % of 68 degree DO
*90 degrees = 7.29 ppm 72.40 % of 59 degree DO or 80.29 % of 68 degree DO


So if you increase the temp from 60 degrees to 90 degrees you only decrease the standard DO 100% saturation rate by 27.6 %. No big whoopee.

Between 68 and 77 degrees there is only a 5.7 % reduction in DO. Too much worry about too little difference in DO. Too few people seem to understand what the real issues really are so they scream low reservoir temps.

If you are going from the "ideal 68 degree reservoir water" DO at 9.08 ppm to 90 degree water DO at 7.29 pm you are reducing the DO by 19.71 %. Not really a big deal for any systems but those systems where roots are hanging in or laying in water, or where the media water logs easily like rock wool. So basically it is not a DO problem but a poor system design that causes limitations. Lowering the temp of the reservoir water still does not let systems like a DWC take advantage of higher growing temps as the difference in DO levels is not that great between 68 degrees and 90 degrees. Even 68 degree water DO is inadequate for plants at high temps even when CO2 and good lighting is provided as the 20% additional DO of the colder water is not enough additional DO.

Plus there is the shock factor that comes from spraying cold reservoir water on the roots of a hot plant or having hot plants roots sitting in cold water is quite stressful. Salts like to diffuse from hot to cold water so this means the colder temperature in the reservoir is wanting to cause nutrient salts to flow from the hot plant fluids into the colder fluids of the roots and the reservoir.

This clearly shows that those worried about the Difference in DO at different temps are over blowing the problem as aeration can easily make up for the different normal DO saturation levels at different temps. The major problem is not really low DO if your aerating but is not the lower DO potential at higher temps but the fact the that plants grow quicker at higher temps and therefore need more oxygen at their roots. This can not be supplied by a system where the roots main source of O2 is from water DO. This means not that the ideal temp for all systems is a low reservoir temp but only for those systems where the roots are dependent on most or all of their O2 coming from DO.

Basically this means about all systems but well draining deep ebb and flow (ie hydroton or equivalent <not rock wool>) or very large tube or deep chamber or tent aero systems where all or nearly all their plants roots are in air rather than laying in water. These systems roots get over 99% of their oxygen from the air so are not dependent on high water DO, therefore they can handle hotter growing temps and reservoir temps.

very informational thread...

I've seen DWC growers get trees with over 3lb per plant (granted lots of light). When Heath Robinson did his famous vertical grow here, on this site, he didn't use any airstones, and the roots were sitting in water most of the time. He ended up getting over 2g/watt on that.

While what you say seems to be mostly true, I'm not certain DO levels in water is a bottleneck , or possibly the roots having 24/7 access to nutrients overrides this bottleneck, which other systems can't provide 24/7 nutrient access.

squarepush3r said:

I've seen DWC growers get trees with over 3lb per plant (granted lots of light). When Heath Robinson did his famous vertical grow here, on this site, he didn't use any airstones, and the roots were sitting in water most of the time. He ended up getting over 2g/watt on that.

While what you say seems to be mostly true, I'm not certain DO levels in water is a bottleneck , or possibly the roots having 24/7 access to nutrients overrides this bottleneck, which other systems can't provide 24/7 nutrient access.

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Many systems can provide 24/7 nutrients. There are systems that provide better nutrient delivery and only supply nutrients a second every minute or two.

I really doubt that you have actually seen any DWC 3 pound grows. That is a yield of 1334 grams. Figure a square meter is about 3.2 feet by 3.2 feet. that is apretty goog six zed area and most seed sellers stae yields usually a third the size you are claimng some dwc growers obtained from a single plant. Maybe you ave heard claims of such. Seed growers are known for over stating what an indoor grow will produce under normal cool reservoir non CO2 supplemented cool temp grows and they very, very seldom ever claim anyone will make over about 550 grams in a square meters space. That is only 1.2 pounds. Of course there talking 10 to 12 weeks of budding and those DWC grows could have been much longer than that or the veg cycle could have been long also.

Yes if you take the time, a long time, and keep both the room temperatures and the reservoir temperatures low you can grow some decent yields even with a fast current DWC in tubes like Heath's vertical or even a standard DWC. A DWC "tree" producing three pounds of dried bud in any reasonable amount of time is very unlikely. Maybe your stating wet weight. That is typically about 1/3 of dry cured bud weight.

Heath did a bit better than air stones by creating many water falls which keep the water turbulent. What a PITA arrangement though Can you imagine the amount of crap that collects at all of those dams he used. Turbulent water does typically have higher DO than is provided by simple air stones though. There are many easier and simpler methods to provide the aeration though. Really the only good advantage to the tubes was to maintain water depth.

Try getting Heath to tell you how long his plants were budding. Likely 12 weeks or more plus the several weeks of vegging. I can pretty much guarantee it took at least twice as long or longer to bud out his clones in his DO limited low temp CO2 free system than in a system where high temps can be done along with CO2 and intense lighting without worrying about DO or temps. Given enough time and low temps and cool reservoirs just about any system can get yields such as you mentioned.

Those yields you boast about that others claim to get are not exceptional yields when you consider the time and Kilowatt hours used to produce them. Myself, I would rather grow 8 or 10 high temp quick SOGs per year than 3 or 4 DO dependent cold crops. Especially when each of those 8 to 10 grows produce as many grams per kilo watt hours as Heath's vertical grow, and that is when growing Indica and Afghanis or Indica/Afghani crosses rather than the sativa/Indica crosses.

Oops I took the post away then I see you responded already. Oh well.

I think it was just in soil actually.

Here's the pic so people know what you're talking about:




I know it's pointless, it's just to prove the system.

You think 20 would do it though really? I wouldn't think so.

Do you have any idea how effective cutting bubbles would be by passing them through stationary cutters versus creating them with the moving needle wheel? The needle wheel is more high speed and active so I'm sure stationary must be less effective, just not sure of the relationship.

OregonMeds said:

You think 20 would do it though really? I wouldn't think so.

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Please do not take that joke seriously. It was merely a carry over knee jerk response to another posters stating he has seen some growers who have obtained three pound yeilds from a single plant grow in a DWC indoors I assume. I was merely joking that this must be an example of a 20 gallon reservoir DWC three pound yield grow only done outdoors.

OregonMeds said:

Oops I took the post away then I see you responded already. Oh well.

I think it was just in soil actually.

Here's the pic so people know what you're talking about:

I know it's pointless, it's just to prove the system.

Click to expand...

How much did this plant yield?

@ Fatman, well, I can't verify if the person was telling the truth or not. The person was using a LOT of light, like 2000W per plant possible. Say, lights on at least 2 sides of the plant, maybe 3. His system is basically a very high speed RDWC, with tons of light, I'm not sure if I can link the pictures here, but ill try


http://www.thcfarmer.com/forums/f131/doubleds-med-patient-bucket-diy-mpb-buckets-7883/#post129742

and heres some flowering pics

http://www.thcfarmer.com/forums/f54/doubleds-new-20-light-medical-garden-2915/#post38993

a lot of his threads were moved due to some security issue, but his plants do look pretty huge. He recently sold the rights to his 'grow system' and its going to be offered by a large company commercially.


Also, Fatman, while you are taking the time to read this and reply, I wanted to ask your opinion on strains. Whats a good breeder/seed company, im looking for a strain with good yield and good dankness/potency, preferably 50/50 indica or more.

Can you give any recommendations or suggestions? thx =]

fatman7574 said:

Please do not take that joke seriously. It was merely a carry over knee jerk response to another posters stating he has seen some growers who have obtained three pound yeilds from a single plant grow in a DWC indoors I assume. I was merely joking that this must be an example of a 20 gallon reservoir DWC three pound yield grow only done outdoors.

Click to expand...

Oh ok I for a second there I was thinking you thought the root mass could actually be shrunk that small under supersaturated ideal conditions as in krusty buckets.

squarepush3r said:

How much did this plant yield?

@ Fatman, well, I can't verify if the person was telling the truth or not. The person was using a LOT of light, like 2000W per plant possible. Say, lights on at least 2 sides of the plant, maybe 3. His system is basically a very high speed RDWC, with tons of light, I'm not sure if I can link the pictures here, but ill try


http://www.thcfarmer.com/forums/f131/doubleds-med-patient-bucket-diy-mpb-buckets-7883/#post129742

and heres some flowering pics

http://www.thcfarmer.com/forums/f54/doubleds-new-20-light-medical-garden-2915/#post38993

a lot of his threads were moved due to some security issue, but his plants do look pretty huge. He recently sold the rights to his 'grow system' and its going to be offered by a large company commercially.


Also, Fatman, while you are taking the time to read this and reply, I wanted to ask your opinion on strains. Whats a good breeder/seed company, im looking for a strain with good yield and good dankness/potency, preferably 50/50 indica or more.

Can you give any recommendations or suggestions? thx =]

Click to expand...

Squarepusher I'm setting up my 4 bin test MPB grow indoors dd's way, and that's the system that's prompted my work on this other thing to try to simplify/streamline dd's system. DD's system is an evolution of krusty buckets and both systems are using up to ~4kw per plant vertical with 1k hps's now and 1500w hps lights are on the market so the sky hasn't been reached yet. Fatman and I don't agree on dd's and krusty yeilds, I believe dd and all the others, too many involved to pull off a lie and krusty buckets have been around over 10 years. I've been following all of them since day one of ea, over a decade, but don't have personal experience with any of them just been in the closet with dirt mostly, doing personal stuff.


Don't get me wrong those yields are not typical though, even in a system like that.

At the same time I believe the hp aero stuff Fatman is on top of is the way to go too, depending on how plants react to each, so comparisons to come at some point. My concern with hp aero is the way the plants are reported to grow shorter than normal, or more like bushes rather than trees.


Nobody knows what the yield was on that outdoor thing or what strain it was, that pic is at least 10 years old. I'm searching out strains for each of the above same as you, so can't help you there.

squarepush3r said:

How much did this plant yield?

@ Fatman, well, I can't verify if the person was telling the truth or not. The person was using a LOT of light, like 2000W per plant possible. Say, lights on at least 2 sides of the plant, maybe 3. His system is basically a very high speed RDWC, with tons of light, I'm not sure if I can link the pictures here, but ill try


http://www.thcfarmer.com/forums/f131/doubleds-med-patient-bucket-diy-mpb-buckets-7883/#post129742

and heres some flowering pics

http://www.thcfarmer.com/forums/f54/doubleds-new-20-light-medical-garden-2915/#post38993

a lot of his threads were moved due to some security issue, but his plants do look pretty huge. He recently sold the rights to his 'grow system' and its going to be offered by a large company commercially.


Also, Fatman, while you are taking the time to read this and reply, I wanted to ask your opinion on strains. Whats a good breeder/seed company, im looking for a strain with good yield and good dankness/potency, preferably 50/50 indica or more.

Can you give any recommendations or suggestions? thx =]

Click to expand...

I like Mandala Seeds. Their prices are exceptionally good. It is hard to get staright indica or indica/afghani crosses though as they sell out quick. About the only thing avilable in a straight indica is a heavy yielding Hashberry. Look in your PM for the lo ink. They do have a lot of good indica/sativa crosses though. Most of them at full size in a rtandard grow are about 8 weeks of budding. Much quicker at clone in SOG with high temps, CO2 etc. Drop the budding time down to about 5 to 6 weeks. They send lots of free seeds with every order.

Looked through the links. Did not see anything that looked like anything over maybe one pound per plant ie about 450 grams which is about what seed suppiers state for a yield for a squat meter. His plants seemed to occupy about a square meter.

Fatman can you explain what it is that happens to the nutrient solution in hp aero that makes it so you can't re-use the stuff, and what if any theories you may have on how that can be overcome. Also would any of those issues translate to a system that used a somewhat high pressure high volume jet, but nothing on the small size you're working with? Theoretically of course.