Multi-Plant Recirculating DWC Test

Xlr8
I am only using the 3 inch because I already own a 100 or two for the vertical satelite and the aeroflo systems. The plants need better anchorage and a 5.5 would probally work best with this size container.

4twenty4all
Dwc is hard to beat in root mass developement as long as its being kept healthy. Do you have alot of experience on a normal dwc system? If so I have a few questions for ya that might help me understand some of the differences from a recirculating dwc and a normal dwc. I personally only dabbled with normal dwc and most of my experience is with veg and cloning. As for recirculating dwc, this is my second grow with a second machine, all the others have been hybrids like the vertical and the aeroflos.

Feel free to pm me Mr Smith. I basically changed mine to RDWC from dual tubs DWC. I did a fair amount of research on it before I made the change. Future expansion plans are to stick with RDWC and I've kinda mapped stuff out accordingly.
 
12twelve, Bassman,
I will be busy harvesting blueberry for a while and will be back later, plus this weekend is special for a important family member and that's going to take up a large chunk of my time.
Bass, thank you, I will pick your brain.
12, I used to go off what's on the label or chart but only use it as a reference to how much of each part I use. My strengh goes by ppm, style of grow, size and age of plant. I have alot to say but me mind is scattered til I am finished with the blueberry and ak sour plants. I think your a very good grower so I would love to talk more about this subject. Thank you.
 
Re: Intermission

How about some bud porn while we wait for this grow to finish?
Blueberry 1

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Blueberry 2

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Blueberry 3

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AK Sour

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Back to the journal
Today is day 44 in flower

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Waterchange
approx 30gal rodi and aged tap mix
240ml BPN part a
840ml BPN part b
100ml dng protek
No need to adjust ph, been keeping waterheight about a 1/2 to 1 inch below the cup.
Seems ph stay more stable at that height. Why, since normal dwc you reduce height by half? Bassman?
Nutes are at 1200 to 1150 ppm, might add blue booster in the next day or two.
Discontinued use of microbe brew and kangaroo rootdrench. Gonna keep it simple and I have seen no benifits from those products.
 
very nice sugar production you got there!!!
 
With DWC or RDWC many growers will start with a higher water level until the roots hit the res. Once the roots hit the res, they start lowering it to a more "stable/suitable" level. The idea is just to get some roots in the water ASAP and not have to wait for them to grow all the way down.
 
My "wut" was just some really dry humor, I knew what you were asking. :thumb:

I can't say that lowering is a goal of any sort really. The biggest benefits I see for rdwc are:

More air in water from circulation.
Efficient cooling.

Side benefits in a setup like yours are ease of refilling/topping off nutes.
Constant knowledge of ph/ppm for the entire grow with less hassle.

With my grow presently, I dont have a fill res and both tubs drain into a T to the pump and return from the chiller to a T that fills from top which adds air to some degree as well. Thus I do have to check both tubs for water level to make sure they stay fairly even. As such, I basically top up in 1-2 gal intervals.

I'm cool with 2-3" below pots as my high point, but I also have pretty deep tubs. This allows for plenty of root mass and they wont be starving for water.

I kinda think I left you with a non answer, but I don't think it's anything to fret over so long as you have a pretty decent amount of well aerated nutrient.
 
With DWC or RDWC many growers will start with a higher water level until the roots hit the res. Once the roots hit the res, they start lowering it to a more "stable/suitable" level. The idea is just to get some roots in the water ASAP and not have to wait for them to grow all the way down.

What this part does is allows you to pull feed pumps sooner and as such less heat is generated in the tubs. As well there is certainly some psychological effect of knowing roots are in the water. They certainly will grow faster too, which is the main goal, thanks to the well aerated bath they sit in.
 
It could very well be (I could be wrong here) less air (I know ratio seems like more) in smaller amount of water. I read someplace (not sure if it's correct) depleted co2 will raise ph. Now as we add mass of root into the pot we actually have less water at the same water level. The water will only hold so much air right? See where I'm going with that?

hmm...Also, an interesting thing I learned was the solubility of oxygen in water is temp dependent. About twice as much dissolves at 0*c as does at 20*c. And at 20c, thats 68f which is where the bad shit can just begin to grow. As such, when we keep or res below 68f, we not only reduce the chance of the bad shit growing in our water but we also put more soluble air into the water.

Now that I've completely confused myself....


I'm stickin with higher level, more air by volume, cold ass water, my plants be happy, less swingy.


Edit: besides, wtf do I know? I'm the new guy !
 
As a general rule, the larger the res, the more stable everything will be since evaporation, and the ingestion of nutes by the plants will have less of an overall effect on PH with a larger volume of nute solution.
 
As a general rule, the larger the res, the more stable everything will be since evaporation, and the ingestion of nutes by the plants will have less of an overall effect on PH with a larger volume of nute solution.

That was the only thing I could think of as well. I'm really at a loss as to why, otherwise, it would affect the PH. Unless there are other factors stabilizing the PH like the timing of the bloom phase and the plant taking up more of certain nutrients. I usually find my PH is most stable around weeks 3-5 of Bloom - it was that way for me with both the Dutch Master line and the BPN 3 part. Maybe that's just me?

Nice looking Blueberry harvest, Mr. Smith. Blueberry sure makes for some pretty buds, huh? :thumb:
 
As a general rule, the larger the res, the more stable everything will be since evaporation, and the ingestion of nutes by the plants will have less of an overall effect on PH with a larger volume of nute solution.

That was the only thing I could think of as well. I'm really at a loss as to why, otherwise, it would affect the PH. Unless there are other factors stabilizing the PH like the timing of the bloom phase and the plant taking up more of certain nutrients. I usually find my PH is most stable around weeks 3-5 of Bloom - it was that way for me with both the Dutch Master line and the BPN 3 part. Maybe that's just me?

Nice looking Blueberry harvest, Mr. Smith. Blueberry sure makes for some pretty buds, huh? :thumb:

What everyone has said is true and correct. Please don't think I don't do my research before I start these long projects. I do miss a few things or misunderstand them until a later date but eventually I get the job done right. Sometimes it takes more than one try.

Xlr8, you gave me half the info I was looking for in experience but what were your water height levels and did you let it fluctuate meaning go up and down?

My experience with dwc is if you keep the water level up too high the center root mass will slime up and cause a stench. Ph will climb up high and then spike down. This does not seem to apply to plants in veg. In veg plant roots stayed white no matter how large I grew it and ph was fairly stable. When I lowered the water height ph dropped for a week or two then stablized and was managable. Main thing I learned about dwc was plants grow real fast but problems can appear real fast and this style of growing needed more attention and maintenance and temp becomes easy to blame problems on. I discarded the project thinking it would be a nightmare if done on a larger scale.
My experience with rdwc has shown me that ph stays more stable when water level is kept high and does a continuous drop when level is lowered having to add 20 to 60ml of ph up daily. I was able to correct that problem with the one plant grow during the last three weeks of flower by keeping the water level high. Temp can no longer be a blame because I have a chiller working with the system. It has been easy to grow on a larger scale as it was on a one plant scale.

Pics of day 49 in flower.

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Mr Smith,

As you know, I'm still a nublet grower. That being said, when you mention slime I think res temps automatically and believe it to be the root cause. At 68f the baddies become alive and grow inside your res. This is inevitably where the slime comes from. My clones right now are a perfect example. I can't hook them up to my chiller with my grow going on still. So I'm forced to use small ice jugs in the res (keep jugs away from roots), and the clone tub is in another larger tub with water that I place ice bags into to chill some from the outside. Obviously I get temp swings above 68f during the course of a week between res changes. As such, yesterday when I did my res change on the clones there was some slime in the tub. The roots are fine. I use hygrozyme, and I do get the temps down most of the time. But I firmly believe thats the cause and the slime is but a symptom. On the other hand, in my grow where I have the chiller working both tubs, there isnt a touch of slime. Not at all ever since I added the chiller.

Now, as for ph dropping, I have not experienced any ph dropping whatsoever. It only goes up for me thus far. My tubs are filled weekly to 6 gals, when they are low about a gal, I add. During the week between res changes I add about 5 gals now while in flower. During veg it was less. But in no cases have I seen ph go down. It's only gone up for me. I use ro water, if that makes a difference.


Just wondering, are you trimming larger fan off at all to give light to lower (nothing to do with ph topic just wondering)?
 
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