My new RDWC setup

Making it up as I go along. I've read about the different types and looked and a bunch of setups for inspiration. All the fittings I've created and printed with my 3d printer, including the 5 way connector for connecting to the reservoire. I've got 1/2" on the top and bottom, from the pump I have an inline fitting that only has a 5mm diameter hole for flow limiting. The pump is one I had sitting around, which turns out to be way overpowered. Currently it takes 5-6 hours before things overflow so I must be pretty close.

I don't think it would mix well enough without a pump after the first fill. When I first filled this system I filled it with water and then mixed the res and turned the pump on. Only after a couple hours of running did the buckets and res finally equalize their ph and ppm. With it just sitting, it doesn't seem like there would be enough flow to equalize everything.

With the RDWC, my understanding is that the circulated volume is a buffer for the nutrients and water. Instead of a plant living in 6 gallons of water, there is now 4 plants per ~40 gallons. The ph of individual buckets wont vary as much and there is only one spot in the system you need to check. With that single point you can also automate things like PH and PPM with some sensors and pumps, keeping the levels closer to optimal for a longer time.

 

If you are checking it more frequently, you wouldn't need a larger reservoir. Just let it run continuous and adjust the control bucket. I think the only advantage of the larger tub is that it will buffer more. If I'm gone for a week or two with the bigger tub it should be at least 'ok' until I can get to it again.

 

Dude I wouldn't leave a RDWC system for more than 2 days without checking, let alone 2 weeks. It def will not be OK. Trust me on this - the price of a successful run is paid in vigilance. Unless you have some way to automatically top off your control res, you will be filling that thing every 12 hours when the plants are big. I had two 20 gallon control reses for eight 5 gallon buckets. The bigger res gives you some wiggle room for topping off, but the downside is more nutrients. Anyway i was shocked at how fast the plants dried the system. For the first two weeks they don't drink much then all the sudden bam, the thing is dry in a day.

PH is a HUGE PITA It will swing. It's like trying to ride on a train by hanging on to the wheel rims.

Edit: I may be sensitive to this, but i am still reeling from a series of horrible failures that could have been avoided with simply watching things closely. Now I'm like a farmer standing in his field with a shotgun looking for varmints. I just pace my op, sniffing for trouble. And I always find it. Just this past week alone i have had four (!!) pump failures. I caught them all, but only because I am watching. There have been WAAAAAAAY to many times I have not caught them. painful. Learn from my pain.

You can do a lot to automate any system. The setup energy (and cost - you priced out any automatic PH adjusters?) is way higher than the maintenance energy. But even with a lot of things automated, you have to watch it like a hawk because things can go wonky.

 

Thanks all for the advice! Definitely like to hear what other people have ran into so I can change things. So far I've solved the overflow issue temporarily with a timer on the pump. One hour on, one hour off. Long term I am going to make a new set of 4 buckets with much larger drains. I've already started on this, currently working on making the fittings.

In this picture, on the left is the current fitting size. Middle is the new drain fitting. Right is a screen to protect against roots that can screw into the back of the fitting.

fittings by toshin posted Jul 3, 2017 at 3:02 PM

 

Another headache with RDWC bucket systems is leaks. The curved surface of the bucket makes a piss poor sealing surface for flat fittings. Silicone goop is the answer. Messy, smelly and takes at least 24 hours to cure and not hurt plants with nasty VOCs. And once you get them all sealed and not leaking....you get to take it all apart again to clean in a few months.

Ahhhhh RDWC.

 

With regards to automation, I am working on an automatic ph adjuster currently. The only parts I don't have already from use in other projects is the ph probe and circuit to connect to a microcontroller. They should arrive in the mail in a few days. I've got a gravity fed float and valve system to keep the reservoir full as well.

Here is a chiller I had from another project that I am going to use if I run into any temperature issues over the summer. I doubt it will be an issue as I live in an area that is pretty mild climate wise.

chiller by toshin posted Jul 3, 2017 at 3:31 PM

 

Two words...flood table. Two more words...easy peesy.

 

I've got the leaking sorted out, exactly as you described. In the 2nd pic in this thread you can see the white silicone that is sealing the reservoir fitting. The fittings and hose require clamps to prevent leaking by design, which also means they are easily removable for cleaning.

All of the fittings are being made on my 3d printer. The bucket fittings include washers that match the curve of the bucket. They are then all sealed with silicone and left for 24 hours before being used. Today I'm working on making larger washers for the bucket drains.

 

The hoses and fittings I'm just planning to replace after grow. I'll recycle them into some other project later. Hose and plastic for the printer is relatively cheap anyways, I still have quite a bit of hose leftover that will last for several more grows.

In my first grow posted here I was testing DWC with a gravity reservoir. I used push-in fittings with 1/2" tubing. between them. In then end I ended up leaving them connecting with a valve between. Pumped the system out, mixed and adjusted in the empty res, pumped that to the res with the plants, fill and mix the empty reservoir and open the valve. I learned a lot about fittings and reservoirs and the result from that grow is what I use for my current profile pic.

In my last grow that failed completely I was experimenting with nutrients and trying to grow in the winter here while coming up with the fittings for the current system that is running now. Several issues were encountered, including what killed the plants in the end. I was unable to attend the plants for about a week and the buckets ran dry. The gravity reservoir system was fine for a week, but buckets were not. In my case it's not an issue of being away, but being unable to care for the plants because of my back injuries from the motorcycle accident.

In the long run the cost of losing a grow or two here while coming up with a reliable system is minimal. While some people would go to a commercial made system, I'm having fun doing this as well and that value alone can't be measured.

 

"Several issues were encountered, including what killedthe plants in the end."

Rofl, sorry man but that's just funny. If it makes you feel better, it happens to the best of us.

 

Turns out the W part of DWC isn't optional

 

That's very cool. I wish I had the curved fittings. I'm not sure I'm enamored of the printer-that-makes-stuff. I'll wait till they make a printer that prints me a Pam Anderson Pre-Tommy clone. Then I'll burn the mental bandwidth needed to learn some new tech.

Building systems is super fun. Good on ya. I can't count the hours I've spend crafting this and that for the op. It's truly a joy. I don't mean to be negative about RDWC. I freaking LOVED my setup for a while. And if I could have afforded some of the fancy equipment to keep the solution just right, I might have stuck with it longer. I just got wore out.

 

The solution to the curved bucket problem is square buckets. Took me quite a while to find some I liked. Ordered them from Uline.

Toshin, if you are writing your own code for the micro controller, consider incorporating a timer watching the pump output that will shut things down if the output is on for too long. Having the pump continue pumping indefinitely in the event of a probe problem could make your plants unhappy real fast.

 

Great idea on the buckets. Just ordered a set.

Will be writing my own code, using an ESP8266. A timer will be a great fallback, currently I have some code that will stop if the ph doesn't change enough based on the amount it is supposed to add. I should be able to figure out how much solution is needed to change the ph in the reservoir system. If it doesn't show enough change after some time it shuts things off.

 

That's a cool little chip. 9600 baud serial connection though, not exactly smokin! Do you know Boolean algebra?

 

Sounds like you've put some thought into it, Toshin. Redundancy is always a good thing. Good luck with your build.