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rDWCNoob

rDWCNoob

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New member here, looking to possibly build an rDWC system. Google led me here and I ran out of page views lol. So I thought Id register and introduce myself. Im a relatively new grower, although Ive had some experience helping others in the past. And, Ive been around and fascinated with cannabis since I was in high school, by far not a total noob to the subject in general, including growing and general cannabis knowledge.

Currently Im growing in rockwool cubes, usually 6 inch but currently in 8 inch cubes. I have a rather small grow cabinet, about 3.8ftx7ft and a single 1000w HPS. It might be a bit overkill for my space but it seemed the most cost effective in the moment to get started. It doesnt really break the bank and it works, however Ive been considering switching out to 2 315w CMH lamps for a wider coverage and more even coverage.

Ive been seriously considering an rDWC system for the last couple weeks and have priced it all out and am now looking for more info on what operating and maintaining a system will be like. Things like how often to change the res, top up, what additives to run (hydro guard seems to be recommended :) etc. Im hoping for a system that would limit the daily watering that Im currently doing. It would be nice to not have to mix up nutes and hand water every single day like I am now. Ive considered a drip or self watering system with cubes, but I think rDWC might work better for me.

My plan so far is to essentially build a 2 plant system in tubs similar to the ones built by PAHydro, theyve got all kinds of Youtube videos on building them. Ive already got a length of 3inch PVC leftover from another project so I was going to use 3 inch PVC for my return lines, connected via a T to the res. And then use 3/4" pvc for my feed lines, again connected via T to the res/pump. If Im looking at the connectors properly, Im going to need a small length of poly tube from the pump to an elbow that will connect to the rigid tube via adapter. Including pumps, basket, airline and tubs Im looking at about 200-300$ CAD to initially set it all up, depending on if I get spare air stones etc and cost of tubs. I was looking at a 400GPH water pump but Im not 100% if its too big or not, Im pretty sure its not too small. The system will be run as a waterfall system, providing me with 2 methods of aeration in case the water or air pump fails, and also to provide more oxygen overall. The pump Im looking at is 7L/m with 2 outlets, one for each plant, with 2inch medium air stones.

Ill probably be spending some time here doing more research on rDWC and general browsing. Hoping to see some sweet grows and fat buds, might post a couple of my own. and perhaps get to know some of you. Cheers to all and happy growing :)

Here is a shot of my first grow in my current grow room at about week 7. Big Bazooka

20210126 005119



And from the top


20210128 002558


20210127 002211
 
tobh

tobh

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Welcome!

Like you, I've a fascination with RDWC as well, though after over a year of designing a system and thinking it through, I just don't believe the real potential of such a system can be realized in a confined space. The cost of both building one and running it just doesn't balance out as effectively as wool does in a small space.

If you're dead set on it, you'll need to dig into the archives here. Circa 2010ish, there were some absolute UC gods around here. There was a guy that built his entire system out of stainless steel and grew trees with liquid cooled vertical bulbs. Shit was nuts.

Anyways, glad to see another hydro guy around, and a new member with some notches on the belt. You're in kind company here.

Now that the introduction is over, lemme pick apart your questions and see if I can provide some answers.

Personally, I don't trust hydroguard. I've used it in the past in recirculating systems and the shit is unreliable. Point blank. It fucks with the pH way too much whenever the bacteria really takes off and it leaves too much up to chance for me personally. I prefer running sterile. 3ml-5ml/gallon 34% h2o2 is the bees knees man. keeps shit clean and stable.

If you're in wool, man... you gotta get autofeed set up. Hand watering is for the birds. Gives you some solid plumbing knowledge too. Get on it, either way you go.

If i were you, I would consider pulling through the system instead of pushing based on how you described your design. You eliminate any positive pressure in the system that way and can move a lot more water. So, you have a T on your 3" PVC that nipples to a 3/4" line, then your pump pulls from that T back into the res. Your 3" carries back to the res and comes under vacuum (not exactly, but an easy concept to describe it as) and pulls water from the res through each site.

I would agree 400gph is too small. I'd be looking at an outboard 1/4 horsepower pump at minimum. Get that water moving through the system with a vigor. Like the roots are living in some rapids or something. With a valve you can dial back the velocity, but I'd let er rip and avoid running air pumps at all since the current will break enough water surface there will be plenty of DO coupled with the h2o2. No air pumps = happy farmer.

Here are my current ladies. Running on unislabs, 4" delta on top of the slabs with floraflex caps and naked feed lines following what I've dubbed a ghetto crop steering fertigation schedule.

DSC 0357
DSC 0356
DSC 0355
DSC 0354
 
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PK1

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I've grown in DWC and imo regardless of the system you go with, if it is not automated than you are going to have to do certain things. In DWC i had to top up the rez and give it ph down here and there. I could of installed few extra things and bought another 500 dollar bluetech auto ph corrector, but i didn't. loL!
Not saying that RDWC or DWC or any other systems are better or worse but they all have one thing in common i think and that is you gona have to put the work in. lol!

I would install a feeding system to the rockwools and keep on going. I think its a easier and less headache.
 
rDWCNoob

rDWCNoob

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Welcome!

<snip>

Ok, I think I understand what youre saying, kinda. I did a quick sketchup of what Im thinking of doing. So If I understand you correctly, youre suggesting it would be better to move the pump outside the res and run it inline with my feed lines, is that correct? I wasnt planning on full automation with a top up res and all the rest of the gadgets, just a simple DWC system with a recirculating res so I dont have to fiddle with multiple top ups etc. I just top up the res when needed, keep an eye on my PPM/Ph, and change the water whatever the recommended interval or when needed, unless Im missing something.

RDWC 2 Plant Fallponic


The one problem I see with having an inline pump is it increases the number of points of failure. If Im correct on the pumps, they all, at least the smaller ones, connect via a barbed connector to a flexible poly tube. That barbed connection, imho, is going to be my most likely point of failure. The rigid PVC is the same we use for water lines in our home, so If I cement it up properly it seems highly unlikely to leak at the cemented joints. And, even then its only the 3" bulkheads and T connectors I have to worry about. The only part of the system under any pressure is the feed lines, but they should be able to handle up to 660 GPH without being pressurized if Im reading correctly ( see: https://flexpvc.com/Reference/WaterFlowBasedOnPipeSize.shtml ). Also, 400GPH is what is used by PAHydro on their fallponic systems for I think a 4 plant system. With this being smaller and only 2 plants, I assumed a 440GPH pump would more than suffice, but now youve got me thinking maybe I dont need the air stones, in which case increasing my flow rate might be beneficial. Ive seen some discussion on these forums suggesting the same, as well as AquaMan in the UC threads saying that you want about 10X the GPH as the total number of gallons in your system, so 400GPH would probably be a little on the low side but not by much. The tubs Im looking at are 120L at the top end, but will probably be run at half that.

If I were to try to run the system at a higher flow rate, how much is a 3/4" poly tube to a barb connector actually going to be able to handle without popping off?

The photo above shows the feed line just above the top of the tubs, but in reality its meant to be just under the top edge, I just didnt feel like taking the time to adjust it, was just a quick sketch specifically for this post. So, the elbow joint connecting to the rigid PVC would actually be in the res under the lid. That way, if theres a leak, it just leaks into my res. So I might be willing to try some higher pressures/flow rates to see how it handles it. Havent bought anything yet, so Im open to any and all suggestions, assuming its not going to overcomplicate things or increase my setup costs significantly.

Thats assuming I ever get around to building it. I still have concerns over water temps though. I know I can get a chiller, but I live in Canada, so I have a 6 month annual subscription to the Great White AC unit lol. However, cooling might be a problem in the summer, assuming Im not going to dish out the money for a water chiller. But Im also concerned about cold in the winter. I have limited space in my grow cabinet and the area outside the cabinet (im in a shed) can get as low as 8C depending on what the weather is, how my vents are setup etc. With wool, I dont have to worry as much as my cabinet stays whatever temp I set it to. But having a res outside my grow room would be problematic unless I get a water heater, maybe an inkbird to automate a cheap one. The plan was to put the res right in the grow cabinet. That way it gets cooled by my AC and ambient in the summer and is kept warm by ambient and my heater in the winter at night(plants night, which is actually day). The HPS puts off more than enough heat when its on to cook my entire shed if not for venting outside, so the heater only runs when its off, even if its -20C outside.

I had actually started building a self watering system with a raspberry pi, cheap moisture sensors and a 4 channel relay, even wrote my own python loop and used conky to display temp, RH and CO2 levels using a USB sensor I bought. It worked fairly well, but I got bored with it and never got around to putting it all together as it was going to take a bit of work and testing to actually make the cheap sensors and DIY electronics work reliably. I would need to first get a bunch of baseline data from the sensors at various known saturation levels and then try to edit my loop to get the timing correct. But my cheap sensors didnt seem to have a very fast reaction time, so I was trying different methods of setting a trigger value which then turned the pump on for X amount of time. Then I got bored of fiddling with it. It was a fun project to mess around with but nothing Id trust my plants to.

If I were to look at going the self watering rockwool route again, would you have any recommendations for a relatively inexpensive kit that could do 2-4 plants?

Also, nice plants, I love the deep green contrasted with the orange and lighter colors in the second photo. Mine have a tendency to lighten up that late into flower, that and the HPS killing my color lol.
 
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tobh

tobh

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here's a real quick sketch on what i mean. the points of failure will most likely be at the bulkheads into the sites and at the res, with a higher power inline pump you can go ahead and run PVC as well. Once the system is setup, you don't really need to worry about being able to move shit around anyways.

PXL 20220115 212942535


In this design, water levels equalize across all sites just by nature of fluid dynamics.

I'm getting ready to take off for a few hours, but I'll come back around and explain this in a bit more detail. I briefly glossed over your response, but haven't fully grok'ed what was said, so apologies on glossing over anything right now. Promise i'll provide more value when I return. Just wanted to drop this here real quick for you to consider.
 
rDWCNoob

rDWCNoob

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here's a real quick sketch on what i mean. the points of failure will most likely be at the bulkheads into the sites and at the res, with a higher power inline pump you can go ahead and run PVC as well. Once the system is setup, you don't really need to worry about being able to move shit around anyways.

<snip>

In this design, water levels equalize across all sites just by nature of fluid dynamics.

I'm getting ready to take off for a few hours, but I'll come back around and explain this in a bit more detail. I briefly glossed over your response, but haven't fully grok'ed what was said, so apologies on glossing over anything right now. Promise i'll provide more value when I return. Just wanted to drop this here real quick for you to consider.

Ok, I was wondering if that was what you were talking about, but what doesnt make sense to me is how youre getting enough DO without a waterfall? The design youre showing simply recirculates. The only real churning is happening in the res on the return. Would I not need to run air stones in this design to get enough churn? Most of the systems Ive seen similar to your design appear to use air stones, in some cases multiple per plant.

The other issue I see with that design is both cost and complexity. Those bulkheads arent cheap. In my design only 3 bulkheads are required. 1 3" tee and 1 3/4", a length of 3/4" and handful of rubber grommets and thats all I need. With yours im looking at 5 bulkheads, 4 3" elbows, 2 3" tees, 3" to 3/4" adapter(not sure if Ive even seen one of these) and a much bigger pump. Not to mention each joint is a possible point of failure. I count upwards of 17 possible points of failure in your design, whereas mine only has 10 and one is in the res. In both designs the water level equalizes the same across the res and 2 tubs. And really, the pumping isnt much different as far as positive pressure either, in both cases the water is only traveling a foot or 2 before being ejected into the res or tubs. The only real difference is mine splits at a tee and I would assume that actually splits the pressure at that point, no? I mean, take away that T and yours is mine in reverse, pulling from 2 res' and feeding one tub. The length of pipe is essentially the same between the pump and res in yours, or the pump and tubs in mine, so I would assume that cancels each other out as far as strain on the pump or pressure in the system.?

Another thing Im wondering about in your design is if the design itself actually necessitates a larger more expensive pump? The entire system is connected as one single system as compared to mine which is 2 separate units, the feed lines and the tubs. Wouldnt the inline version have more strain on the pump by pulling from a pipe vs pulling from an open res?
 
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imo both designs would work. The T inlet will allow enough waterfall for water to agitate and mix air. @tobh design relies more on the water travel which would agitate the water and create air pockets.
Either way you are going to need a strong pump to have enough momentum. Air stones are not needed if the water is travelling and the surface breaking.
Also, you are running a RDWC not DWC
 
rDWCNoob

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imo both designs would work. The T inlet will allow enough waterfall for water to agitate and mix air. @tobh design relies more on the water travel which would agitate the water and create air pockets.
Either way you are going to need a strong pump to have enough momentum. Air stones are not needed if the water is travelling and the surface breaking.
Also, you are running a RDWC not DWC
Yes I realize its RDWC, I just meant my intentions in possibly building a system was for it to be one step off a DWC, and not a fully automated RDWC with control bucket, res, Blue labs unit and automatic top off or anything like that. But I do appreciate the second opinion on the design. My wallet might thank you lol. I just want to keep it as simple as possible with as few parts as possible, but still work properly. Again, if I even get around to building one. My current crop is almost done and my next is already in wool so it would be a while before I even decide if I want to build it.
 
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you just have to remember that @tobh design doesn't have the stress to the roots that your design has. When the water is shooting in the buckets where the plants roots are, it can potentially damage the roots but then again, it all depends what you put where and how it is designed. I think tobh has a good point of putting the waterfall back to rez, which is the section that holds the entire system together and water agitation is needed. No more need for air bubbles,, air pumps.
 
tobh

tobh

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cutting this hella short as my state of mind is one track atm, but running high concentration of h2o2 ensures high concentration of DO. chemistry here is simple. run 29% - 34% h2o2 at 5ml/gallon and fuck an air stone. keep the water moving and you can have the solution still and there's more than enough o2 for the roots to be happy.

will get back to this thread in a couple days. gotta officiate a wedding tomorrow then back to the grind.
 
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rDWCNoob

rDWCNoob

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cutting this hella short as my state of mind is one track atm, but running high concentration of h2o2 ensures high concentration of DO. chemistry here is simple. run 29% - 34% h2o2 at 5ml/gallon and fuck an air stone. keep the water moving and you can have the solution still and there's more than enough o2 for the roots to be happy.

will get back to this thread in a couple days. gotta officiate a wedding tomorrow then back to the grind.
Ok and no prob, do what you gotta do and good luck with the wedding. I appreciate any and all responses and realize that not everyone has the time to write out a big ass wall of text to match mine. I actually walk away and come back to them multiple times before posting anyway, thats why my responses are often a day apart.

Regarding the H2O2, Im seeing a lot of conflicting info about using it. Some seem to swear by it, others say it should only be used to treat root rot, and still others Ive seen say they dont use it at all. Ive found one post that stated that its best used in organic nutes because if there is no organic material in the solution for it to attack, it then start killing off the roots. Not enough to kill the plant, but enough to slow growth. Perhaps I should mention I use mostly fully synthetic nutrient salt type fertilizer.

There actually appears to be a lot of conflicting info on RDWC in general. Some say simple is better, others recommend UC systems over all else, and some seem happy with their DWC in 5gal buckets. So just a warning, if it seems like Im not listening, I am. But I also seek out multiple sources and opinions and then try to make sense of it all by questioning what people are telling me. Then I go do whatever I feel is most correct, or that seems like it would work best for me in my specific situation.

For example, when I started I saw all the recommendations of starting in soil. After MUCH reading and looking at grows, especially beginner ones, I very much disagree that a noob should start in soil. Hand watered rockwool is the way to go for a beginner. Every beginner I see, usually has deficiency problems, yellow leaves on the bottom of small plants just out of seedling stage, fights with bugs etc. I started my first grow with rockwool and had none of that. First plant didnt like my pH so I added an extra drop of pH down and boom, healthy plant. Ive not seen any deficiencies at all, no bugs, no mixing soil, no mess, impossible to overwater. The only thing you have to get right really is pH and a balanced nute. Also, Ive seen 6 inch cubes grow plants as big as a 10 or 20 gal pot, easily A buddy of mine uses coco and has these huge fabric pots, giant bags of coco, worm casings, the works. His plants and buds get no bigger than mine in a tiny little 6 inch cube.

So yeah, dont be discouraged by my responses if I keep arguing against your recommendations, I am listening and do appreciate the info. But, Im stubborn and like doing my own thing, after a lot of research from multiple sources of course.

Cheers
 
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tobh

tobh

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Alright, I'm back around. Gonna get caught up on this.

Ok, I think I understand what youre saying, kinda. I did a quick sketchup of what Im thinking of doing. So If I understand you correctly, youre suggesting it would be better to move the pump outside the res and run it inline with my feed lines, is that correct? I wasnt planning on full automation with a top up res and all the rest of the gadgets, just a simple DWC system with a recirculating res so I dont have to fiddle with multiple top ups etc. I just top up the res when needed, keep an eye on my PPM/Ph, and change the water whatever the recommended interval or when needed, unless Im missing something.

View attachment 1206595

The one problem I see with having an inline pump is it increases the number of points of failure. If Im correct on the pumps, they all, at least the smaller ones, connect via a barbed connector to a flexible poly tube. That barbed connection, imho, is going to be my most likely point of failure. The rigid PVC is the same we use for water lines in our home, so If I cement it up properly it seems highly unlikely to leak at the cemented joints. And, even then its only the 3" bulkheads and T connectors I have to worry about. The only part of the system under any pressure is the feed lines, but they should be able to handle up to 660 GPH without being pressurized if Im reading correctly ( see: https://flexpvc.com/Reference/WaterFlowBasedOnPipeSize.shtml ). Also, 400GPH is what is used by PAHydro on their fallponic systems for I think a 4 plant system. With this being smaller and only 2 plants, I assumed a 440GPH pump would more than suffice, but now youve got me thinking maybe I dont need the air stones, in which case increasing my flow rate might be beneficial. Ive seen some discussion on these forums suggesting the same, as well as AquaMan in the UC threads saying that you want about 10X the GPH as the total number of gallons in your system, so 400GPH would probably be a little on the low side but not by much. The tubs Im looking at are 120L at the top end, but will probably be run at half that.

If I were to try to run the system at a higher flow rate, how much is a 3/4" poly tube to a barb connector actually going to be able to handle without popping off?

The photo above shows the feed line just above the top of the tubs, but in reality its meant to be just under the top edge, I just didnt feel like taking the time to adjust it, was just a quick sketch specifically for this post. So, the elbow joint connecting to the rigid PVC would actually be in the res under the lid. That way, if theres a leak, it just leaks into my res. So I might be willing to try some higher pressures/flow rates to see how it handles it. Havent bought anything yet, so Im open to any and all suggestions, assuming its not going to overcomplicate things or increase my setup costs significantly.

Thats assuming I ever get around to building it. I still have concerns over water temps though. I know I can get a chiller, but I live in Canada, so I have a 6 month annual subscription to the Great White AC unit lol. However, cooling might be a problem in the summer, assuming Im not going to dish out the money for a water chiller. But Im also concerned about cold in the winter. I have limited space in my grow cabinet and the area outside the cabinet (im in a shed) can get as low as 8C depending on what the weather is, how my vents are setup etc. With wool, I dont have to worry as much as my cabinet stays whatever temp I set it to. But having a res outside my grow room would be problematic unless I get a water heater, maybe an inkbird to automate a cheap one. The plan was to put the res right in the grow cabinet. That way it gets cooled by my AC and ambient in the summer and is kept warm by ambient and my heater in the winter at night(plants night, which is actually day). The HPS puts off more than enough heat when its on to cook my entire shed if not for venting outside, so the heater only runs when its off, even if its -20C outside.

I had actually started building a self watering system with a raspberry pi, cheap moisture sensors and a 4 channel relay, even wrote my own python loop and used conky to display temp, RH and CO2 levels using a USB sensor I bought. It worked fairly well, but I got bored with it and never got around to putting it all together as it was going to take a bit of work and testing to actually make the cheap sensors and DIY electronics work reliably. I would need to first get a bunch of baseline data from the sensors at various known saturation levels and then try to edit my loop to get the timing correct. But my cheap sensors didnt seem to have a very fast reaction time, so I was trying different methods of setting a trigger value which then turned the pump on for X amount of time. Then I got bored of fiddling with it. It was a fun project to mess around with but nothing Id trust my plants to.

If I were to look at going the self watering rockwool route again, would you have any recommendations for a relatively inexpensive kit that could do 2-4 plants?

Also, nice plants, I love the deep green contrasted with the orange and lighter colors in the second photo. Mine have a tendency to lighten up that late into flower, that and the HPS killing my color lol.
I wouldn't stress on the bar fittings. If you absolutely must use them (in my design you can run PVC hardline for all the plumbing), some worm drive hose clamps will ensure the poly tube will not come off the barb fittings. We used to do just that with low pressure hydraulic lines in the oil fields -- low pressure being anything under 1,000 PSI. Never had issues.

I also wouldn't worry about res temps unless they climb up over 75F+. In fact, running the res at 72F will aide in more rapid growth than keeping it lower. You would also avoid running into problems with pathogens with h2o2, and DO wouldn't be a concern as I mentioned previously. An aquarium heater would do well to keep things at least at a reasonable temp I would think, especially if you insulated the epicenter reasonably well. Hell, get ahold of one of those camping ice chests and you've got yourself a fantastic res that's durable as hell and won't be impacted by temps as severely.

would love to see that project! i'm a long time fan of conky and use python in my day job, would be super cool to take a look at and plays into something I've been wanting to do for a while. Fuck a grosens or aroya if there's a cheaper alternative with a raspberry pi and some arduino sensors..

As for wool, depending on your space, I highly recommend delta blocks on top of unislabs. Cheap, clean, and overall ridiculously impressive for what they are. Using this method, I wrote off going UC until I have the room to really realize the potential of a UC system -- meaning until I have space to run at least 4k HPS and grow trees in a sealed environment.

Ok and no prob, do what you gotta do and good luck with the wedding. I appreciate any and all responses and realize that not everyone has the time to write out a big ass wall of text to match mine. I actually walk away and come back to them multiple times before posting anyway, thats why my responses are often a day apart.

Regarding the H2O2, Im seeing a lot of conflicting info about using it. Some seem to swear by it, others say it should only be used to treat root rot, and still others Ive seen say they dont use it at all. Ive found one post that stated that its best used in organic nutes because if there is no organic material in the solution for it to attack, it then start killing off the roots. Not enough to kill the plant, but enough to slow growth. Perhaps I should mention I use mostly fully synthetic nutrient salt type fertilizer.

There actually appears to be a lot of conflicting info on RDWC in general. Some say simple is better, others recommend UC systems over all else, and some seem happy with their DWC in 5gal buckets. So just a warning, if it seems like Im not listening, I am. But I also seek out multiple sources and opinions and then try to make sense of it all by questioning what people are telling me. Then I go do whatever I feel is most correct, or that seems like it would work best for me in my specific situation.

For example, when I started I saw all the recommendations of starting in soil. After MUCH reading and looking at grows, especially beginner ones, I very much disagree that a noob should start in soil. Hand watered rockwool is the way to go for a beginner. Every beginner I see, usually has deficiency problems, yellow leaves on the bottom of small plants just out of seedling stage, fights with bugs etc. I started my first grow with rockwool and had none of that. First plant didnt like my pH so I added an extra drop of pH down and boom, healthy plant. Ive not seen any deficiencies at all, no bugs, no mixing soil, no mess, impossible to overwater. The only thing you have to get right really is pH and a balanced nute. Also, Ive seen 6 inch cubes grow plants as big as a 10 or 20 gal pot, easily A buddy of mine uses coco and has these huge fabric pots, giant bags of coco, worm casings, the works. His plants and buds get no bigger than mine in a tiny little 6 inch cube.

So yeah, dont be discouraged by my responses if I keep arguing against your recommendations, I am listening and do appreciate the info. But, Im stubborn and like doing my own thing, after a lot of research from multiple sources of course.

Cheers
Oh, no discouragement man. You're speaking my language on the beginner argument, 100%. I despise that piece of advice. Sure, more lessons can be gleaned from soil and the state of helplessness that comes from fucking up is a valuable experience in of itself (in the sense you learn not to fuck up again). There are much easier methods for a beginner, but I digress.

As for the h2o2 destroying roots thing -- sure, h2o2 will eat your skin if you get it on you. The root damage that occurs is due to running too high of concentrations. IME, I've never seen it though and I run as high as 5ml/gallon at any given stage of plant life. Hell, I hardly even measure it out accurately. A shot glass full is a rough enough measurement for the volume of my res. If one is running it at some insane concentration, like 10ml+/gallon, then yeah, there will definitely be negative consequences. I just found the UX to be much friendlier than running a live system. Live systems are like a one-part IPM. I personally don't like leaving things to chance -- that's why I run salt nutrients, and h2o2. I trust the chemistry of the stuff I use, and my abilities to understand proper applications than hoping that the bacterial cultures will take hold before pathogens do and will prevent pathogens from overpowering them.

Please, continue to do your research. UC looks so damn simple and easy, but there are a lot of additional variables that come into play in such a system and like rockwool there is a lot of opportunity to really fuck up, with the biggest con being you could end up with several dozen gallons of solution all over your grow space.
 
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rDWCNoob

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Alright, I'm back around. Gonna get caught up on this.


I wouldn't stress on the bar fittings. If you absolutely must use them (in my design you can run PVC hardline for all the plumbing), some worm drive hose clamps will ensure the poly tube will not come off the barb fittings. We used to do just that with low pressure hydraulic lines in the oil fields -- low pressure being anything under 1,000 PSI. Never had issues.

I also wouldn't worry about res temps unless they climb up over 75F+. In fact, running the res at 72F will aide in more rapid growth than keeping it lower. You would also avoid running into problems with pathogens with h2o2, and DO wouldn't be a concern as I mentioned previously. An aquarium heater would do well to keep things at least at a reasonable temp I would think, especially if you insulated the epicenter reasonably well. Hell, get ahold of one of those camping ice chests and you've got yourself a fantastic res that's durable as hell and won't be impacted by temps as severely.

would love to see that project! i'm a long time fan of conky and use python in my day job, would be super cool to take a look at and plays into something I've been wanting to do for a while. Fuck a grosens or aroya if there's a cheaper alternative with a raspberry pi and some arduino sensors..

As for wool, depending on your space, I highly recommend delta blocks on top of unislabs. Cheap, clean, and overall ridiculously impressive for what they are. Using this method, I wrote off going UC until I have the room to really realize the potential of a UC system -- meaning until I have space to run at least 4k HPS and grow trees in a sealed environment.


Oh, no discouragement man. You're speaking my language on the beginner argument, 100%. I despise that piece of advice. Sure, more lessons can be gleaned from soil and the state of helplessness that comes from fucking up is a valuable experience in of itself (in the sense you learn not to fuck up again). There are much easier methods for a beginner, but I digress.

As for the h2o2 destroying roots thing -- sure, h2o2 will eat your skin if you get it on you. The root damage that occurs is due to running too high of concentrations. IME, I've never seen it though and I run as high as 5ml/gallon at any given stage of plant life. Hell, I hardly even measure it out accurately. A shot glass full is a rough enough measurement for the volume of my res. If one is running it at some insane concentration, like 10ml+/gallon, then yeah, there will definitely be negative consequences. I just found the UX to be much friendlier than running a live system. Live systems are like a one-part IPM. I personally don't like leaving things to chance -- that's why I run salt nutrients, and h2o2. I trust the chemistry of the stuff I use, and my abilities to understand proper applications than hoping that the bacterial cultures will take hold before pathogens do and will prevent pathogens from overpowering them.

Please, continue to do your research. UC looks so damn simple and easy, but there are a lot of additional variables that come into play in such a system and like rockwool there is a lot of opportunity to really fuck up, with the biggest con being you could end up with several dozen gallons of solution all over your grow space.

Nice! Another linux guy lol. Not many of us around these days. My work is shifting away from open source linux stuff in favor of vendor supported solutions, but there are still systems that end up either built on Redhat/CentOS or Debian based stuff too. Ill have to dig around to find the code on my PC or boot up the pi and grab the files. The pumps I bought from amazon are just cheap little 5v pumps and some tubing along with the moisture sensors and relay. You can buy the kit either with or without the Arduino Uno. With the Uno, they give you sample code that will work with the Uno for up to 4 plants, however they dont give instructions for a pi, and the only sample code they give is for a single plant. I was hoping to do 4 and I already had a pi, didnt want to spend more money on an Uno so, I decided to jump in and learn how to use the GPIO pins on the pi.

Essentially the sensors are analog, so first off you need to purchase an ADC. Theres a Python ADC library created by AdaFruit that allows you to query the sensors via the I2C bus. The Adafruit library allows you to call one of 4 channels and returns a numerical value for the analogue sensor reading. Then on the GPIO pins you can connect a 4 channel relay to control the pumps. Raspberry Pi offers its own GPIO library thats pretty easy to use. You just call the setup function which clears the pin settings and sets the pins default state from high to low, then call the appropriate pin # for the relay channel you want to turn on and set the channel to high to flip the relay on. You can then just use a sleep function to turn on the pump for a specified time and then call the function to reset the pin back to its default state.

I was trying to run a while loop that would run every 5 mins, and then in nested loops it would query the value of the first sensor, and if the value was above a certain value(higher was dryer), it would then call the function to turn on the corresponding pump, sleep for X seconds, then turn off the pump, else sleep for 5 sec and move on to the next plant. Once each plant had been queried and watered if needed, the primary loop would sleep for 5 mins and then start over. What I wanted to do at first was setup each watering loop to query the sensor and water until the sensor reached a certain value of wetness, and then stop. That way I could keep each plant at a specific moisture level. However, the sensors had a pretty serious delay in reading the moisture levels within the rockwool. They seemed fine when testing with a glass of water, put the sensor in, it read wet, pull it out and it would read dry. But as soon as I got it in the rockwool, there didnt seem to be much movement in the sensor readings even after watering till runoff. That and each sensor was giving slightly different values for fully saturated, so I was going to have to figure out what was truly dry for each sensor and then modify my code so that each sensor loop was actually looking for a different value rather than all the same. That and have it water for a specific amount of time instead of via sensor reading as the delay would have flooded my growroom.

Also, if you plan on running a res any deeper than like 6 inches, you would need some of the white waterproof self soldering connectors. The power cables for the pumps were not very long. I got the connectors but I didnt have a heat gun available and used my lighter. It worked but not very well, and my soldering skills are pretty amateur. Im comfortable doing it, have done lots of it, but my joints arent always ideal lol. I mean, soldering up a larger gauge wire for the power harness on a homemade drone, not a problem. Soldering together 22 AWG cables and pins on small electronics? Thats a tad more difficult... or maybe delicate is a better word. So I wasnt willing to trust my plants and nutes to possible bad solder joints and cheap ass pumps and sensors that could die on me at any time. However, I learned quite a bit about the GPIO stuff on a pi and how to control a relay with them. I think with better pumps and a bigger relay Id be comfortable writing a simple time based loop to control the pump on a timer rather than sensor readings, but its not on my radar at the moment. I should also mention that while I work in IT, Im not a programmer so all this was new to me although I had taken some python course a long time ago.

The conky stuff was pretty simple. So as you probably know you can just specify whatever text you want to display and one of the functions you can use in that txt is to call a script. So youre just entering into your conkyrc:

Plant 1: (script) #script would query the sensor and then return one of 3 values, wet, happy or dry depending on what range the value fell in
Plant 2: (script)
...
CO2 Level: (script) #the USB sensor I bought had linux drivers but not very good ones. I couldnt get the GUI to install, but the command line query worked perfectly, even allowed different formatting and return values

I also have a 7 inch display for it and just messed with the position of the transparent conky window and increased text size to fill the screen and had a nice little status display for my grow room. That part I definitely want to revisit and get setup again. Id also like to get some more sensors for temp and RH etc, but those are nice to haves and not necessary so Im not in any hurry.


So, back to RDWC. Ive taken into account your suggestion and have come up with a new design as seen below. Youll notice the return line is split into a T that goes to 2 Venturi valves. Ive been reading about them and have seen some uses in aquariums and aquaponics. Now, correct me if Im wrong, but the reason I dont want airstones is simply because the pump adds both noise and most notably heat into your water supply, correct? With the venturi valves you get the same kind of aeration as an airstone, except there is zero heat and zero noise, not to mention doesnt draw any power. My understanding at this point is that while it is theoretically possible to have too much aeration that could damage the plants/roots, it is not feasible/easy to achieve that level of aeration in a homemade RDWC. Also, more DO is better all the way up to that critical saturation point. So, I decided to integrate them into the design. One thing with a venturi valve though, is that is does restrict flow. Which is why I split the pipe up into a T, to try to relieve any flow restriction caused by it.

View attachment 1208139


One concern I have with this design, is that both the intake and return lines are on the same side of the tub. Will this cause the flow to short circuit itself, or will there be enough flow pressure on the intake to churn everything up enough to avoid any dead spots in the water circulation?

Another question I have is would it hurt to have the intake pipes sit a little higher than the return pipes? Im asking because the design of some of the tubs out there leaves me with little room for 2 3" T pipes to fit due to the tubs not having totally flat surfaces. If I could have my intake pipes slightly higher it might allow me to squish things together a little more on the available flat surface.

Another design idea Ive seen online has the intake pointing down about an inch from the bottom, filling the tub from the bottom up, and then the return facing up near the surface , drawing water from the top. In the demonstration I watched they used colored water to show how cooler water displaces the warmer from the bottom up in such a system. Assuming your water coming from your res is slightly cooler than that which is in your tubs, would it make sense to setup the intake and return in such a manner? Essentially the return would collect the warmer, stale water from the top of the tub, while the intake would replenish the whole tub from bottom to top. In my design it would look something like this:

RDWC 2 Plant Fallponic 1


The idea would be for the plants to sit closer to the res in hopes that the roots would not reach the return line as easily. What worries me about this is what happens if the water level gets too low for the intake pipe? How far will my water level drop each day? That and Im adding more complexity and cost lol. Could it work though, or is this a disaster waiting to happen? I could potentially cut the one end off the elbows so the intake could sit lower and the return would be further under the surface?
 
rDWCNoob

rDWCNoob

36
18
Nice! Another linux guy lol. Not many of us around these days. My work is shifting away from open source linux stuff in favor of vendor supported solutions, but there are still systems that end up either built on Redhat/CentOS or Debian based stuff too. Ill have to dig around to find the code on my PC or boot up the pi and grab the files. The pumps I bought from amazon are just cheap little 5v pumps and some tubing along with the moisture sensors and relay. You can buy the kit either with or without the Arduino Uno. With the Uno, they give you sample code that will work with the Uno for up to 4 plants, however they dont give instructions for a pi, and the only sample code they give is for a single plant. I was hoping to do 4 and I already had a pi, didnt want to spend more money on an Uno so, I decided to jump in and learn how to use the GPIO pins on the pi.

Essentially the sensors are analog, so first off you need to purchase an ADC. Theres a Python ADC library created by AdaFruit that allows you to query the sensors via the I2C bus. The Adafruit library allows you to call one of 4 channels and returns a numerical value for the analogue sensor reading. Then on the GPIO pins you can connect a 4 channel relay to control the pumps. Raspberry Pi offers its own GPIO library thats pretty easy to use. You just call the setup function which clears the pin settings and sets the pins default state from high to low, then call the appropriate pin # for the relay channel you want to turn on and set the channel to high to flip the relay on. You can then just use a sleep function to turn on the pump for a specified time and then call the function to reset the pin back to its default state.

I was trying to run a while loop that would run every 5 mins, and then in nested loops it would query the value of the first sensor, and if the value was above a certain value(higher was dryer), it would then call the function to turn on the corresponding pump, sleep for X seconds, then turn off the pump, else sleep for 5 sec and move on to the next plant. Once each plant had been queried and watered if needed, the primary loop would sleep for 5 mins and then start over. What I wanted to do at first was setup each watering loop to query the sensor and water until the sensor reached a certain value of wetness, and then stop. That way I could keep each plant at a specific moisture level. However, the sensors had a pretty serious delay in reading the moisture levels within the rockwool. They seemed fine when testing with a glass of water, put the sensor in, it read wet, pull it out and it would read dry. But as soon as I got it in the rockwool, there didnt seem to be much movement in the sensor readings even after watering till runoff. That and each sensor was giving slightly different values for fully saturated, so I was going to have to figure out what was truly dry for each sensor and then modify my code so that each sensor loop was actually looking for a different value rather than all the same. That and have it water for a specific amount of time instead of via sensor reading as the delay would have flooded my growroom.

Also, if you plan on running a res any deeper than like 6 inches, you would need some of the white waterproof self soldering connectors. The power cables for the pumps were not very long. I got the connectors but I didnt have a heat gun available and used my lighter. It worked but not very well, and my soldering skills are pretty amateur. Im comfortable doing it, have done lots of it, but my joints arent always ideal lol. I mean, soldering up a larger gauge wire for the power harness on a homemade drone, not a problem. Soldering together 22 AWG cables and pins on small electronics? Thats a tad more difficult... or maybe delicate is a better word. So I wasnt willing to trust my plants and nutes to possible bad solder joints and cheap ass pumps and sensors that could die on me at any time. However, I learned quite a bit about the GPIO stuff on a pi and how to control a relay with them. I think with better pumps and a bigger relay Id be comfortable writing a simple time based loop to control the pump on a timer rather than sensor readings, but its not on my radar at the moment. I should also mention that while I work in IT, Im not a programmer so all this was new to me although I had taken some python course a long time ago.

The conky stuff was pretty simple. So as you probably know you can just specify whatever text you want to display and one of the functions you can use in that txt is to call a script. So youre just entering into your conkyrc:

Plant 1: (script) #script would query the sensor and then return one of 3 values, wet, happy or dry depending on what range the value fell in
Plant 2: (script)
...
CO2 Level: (script) #the USB sensor I bought had linux drivers but not very good ones. I couldnt get the GUI to install, but the command line query worked perfectly, even allowed different formatting and return values

I also have a 7 inch display for it and just messed with the position of the transparent conky window and increased text size to fill the screen and had a nice little status display for my grow room. That part I definitely want to revisit and get setup again. Id also like to get some more sensors for temp and RH etc, but those are nice to haves and not necessary so Im not in any hurry.


So, back to RDWC. Ive taken into account your suggestion and have come up with a new design as seen below. Youll notice the return line is split into a T that goes to 2 Venturi valves. Ive been reading about them and have seen some uses in aquariums and aquaponics. Now, correct me if Im wrong, but the reason I dont want airstones is simply because the pump adds both noise and most notably heat into your water supply, correct? With the venturi valves you get the same kind of aeration as an airstone, except there is zero heat and zero noise, not to mention doesnt draw any power. My understanding at this point is that while it is theoretically possible to have too much aeration that could damage the plants/roots, it is not feasible/easy to achieve that level of aeration in a homemade RDWC. Also, more DO is better all the way up to that critical saturation point. So, I decided to integrate them into the design. One thing with a venturi valve though, is that is does restrict flow. Which is why I split the pipe up into a T, to try to relieve any flow restriction caused by it.

View attachment 1208139


One concern I have with this design, is that both the intake and return lines are on the same side of the tub. Will this cause the flow to short circuit itself, or will there be enough flow pressure on the intake to churn everything up enough to avoid any dead spots in the water circulation?

Another question I have is would it hurt to have the intake pipes sit a little higher than the return pipes? Im asking because the design of some of the tubs out there leaves me with little room for 2 3" T pipes to fit due to the tubs not having totally flat surfaces. If I could have my intake pipes slightly higher it might allow me to squish things together a little more on the available flat surface.

Another design idea Ive seen online has the intake pointing down about an inch from the bottom, filling the tub from the bottom up, and then the return facing up near the surface , drawing water from the top. In the demonstration I watched they used colored water to show how cooler water displaces the warmer from the bottom up in such a system. Assuming your water coming from your res is slightly cooler than that which is in your tubs, would it make sense to setup the intake and return in such a manner? Essentially the return would collect the warmer, stale water from the top of the tub, while the intake would replenish the whole tub from bottom to top. In my design it would look something like this:

View attachment 1208250

The idea would be for the plants to sit closer to the res in hopes that the roots would not reach the return line as easily. What worries me about this is what happens if the water level gets too low for the intake pipe? How far will my water level drop each day? That and Im adding more complexity and cost lol. Could it work though, or is this a disaster waiting to happen? I could potentially cut the one end off the elbows so the intake could sit lower and the return would be further under the surface?
looks like I lost the first attachment got stripped, probably because I left the window open too long lol. Here is the original image that was supposed to embedded

RDWC 2 Plant Fallponic
 
tobh

tobh

Supporter
4,073
263
@Aqua Man join the convo bud.

So, I've used venturi pumps in the past. They work highly effectively, but in a system like this I wouldn't bother, honestly. So long you get the flow going enough and use h2o2, you don't need to worry about aeration. @Dirtbag and I both leave our reservoirs stagnant aside from when mixing a new res. I run a mixing pump during that time and will let it run for about an hour after I'm done making a new res, then turn it off till the next time. Haven't had any issues at all.

My big concern with this new design is the fact that the inlets and outlets are on the same side. As you mentioned, this looks like it will cause short circuiting and dead spots especially in the corners of the tubs. I also don't like the idea of the elbows. that's just more problemats created when the roots get crazy. ideally you'd have the solution run end to end through the tubs, and that would allow for maximum velocity of the solution vs the solution have to churn and change directions. Movement is the biggest factor that makes UC so impressive, after all.

Having the inlet sit higher than the outlet shouldn't be an issue, so long the solution level never dropped below the top of the outlet's pipe orifice. If that happens, the pump will start sucking air, your water will go completely stagnant and the roots will drown, fast. Gotta make sure things keep moving. It's hard to say how much the water levels will drop as that's highly dependent on a ton of different factors. In my last recirculating system at the peak of flower, my water level was dropping anywhere from 3" to 6" daily. It was intense. The res held 15 gallons and I was having to add at least one 5 gallon bucket of water every single day to keep up with it. YMMV.

Air pumps have these problems:

- Agitation from the stones can damage roots if used in excess
- They're noisy
- They add heat to your solution
- More shit to trip over
- They're noisy
- There have been some claims that they increase CO2 concentrations in the solution. This does two things. 1. acidifies the solution and 2. roots breathe oxygen, not CO2.
- They're really, annoyingly noisy
- Air stones disintegrate over time in acidic solutions. Yes, 5.5 pH solution is acidic. Yes, it will corrode the adhesives or binders or whatever the air stones are held together with.
- Did I say they're fuckin noisy?

All that can be avoided by just not using them. They're unnecessary, I don't care who says otherwise. There are better solutions out there that will perform just as well and don't require all the BS air pumps and stones do.

And finally, yeah, I'm an old Linux dude. Prefer FreeBSD but the hardware support seems to lag about 10 years behind everything else so I run Debian as my DD and on all my servers. Used to be a Gentoo guy, but after I got my first dev job and didn't have time to fix all the shit that breaks every time Gentoo receives an update I said fuckit and converted to Debian. Haven't looked back since. Still run a couple FreeBSD boxes and a FreeNAS box for various things though.
 

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