Looking for opinions on my RDWC system design

guabasa

Member
Hi everyone! I'm coming back for my second grow and have decided to move from DWC to RDWC. So after lots of research I've completed my design in sketchup and am getting ready to start purchasing everything. Before I do that, I was looking for some opinions on the system design and some of the components.

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Quick rundown of the system:

It's a waterfall system (feed lines go into the top of the buckets) with 3/4" feed lines and 3" return lines. Feed lines will be black PVC and return lines will be black ABS. The feed lines will be aerated using Flow Rite PowerStream Nozzle Aerators. No plans on using air stones or air pumps.

RO unit will be connected to an outdoor hose faucet which I've installed in my bathroom shower, from there it will fill up a 150 gallon top off res which will be connected to the control bucket with 3/4" PVC pipe, it will operate manually with a true union ball valve I need to open to fill up the system with 0 ppm RO water once a week. This will be gravity fed and will have a float valve to automatically shut off the RO unit.

Inside the tents our plant sites will be elevated to 8.5 inches, the control bucket will be elevated to 4 inches.

The control bucket will have a hole in the bottom which will be piped directly to the pump. I'm thinking about a Hydor 1600GPH pump, will this be enough for 8 plant sites, 13 gallons each? Important to mention is I will be starting with only one tent, so 4 plant sites + control bucket at the beginning, planning to double the system later on but would like to purchase a big enough pump right from the start. The Hydor Seltz D pumps have a controllable speed feature with 6 settings you can choose from, for example, the 500GPH pump can be set to: 83 gph, 167 gph, 250 gph, 333 gph, 417 gph and 500 gph. They have 500, 750, 1000, 1600, 2400 and 3600gph models. Which one would you choose for a 4 and 8 plant system? Considering they can be dialed in.

Coming out of the pump there will be a pvc manifold with 4 true union ball valves. One goes to 4 sites in one tent, another goes to the second tent, another goes back to the control bucket for aeration and the 4th will be a drain line which goes directly to the tub in the bathroom. Idea is that when I need to drain the system I open the drain line and close the other three valves and it drains the entire system.

All piping will have pvc unions in key spots so I can easily dissasemble the entire system if need be, without having to cut and throw out a bunch of pipe.

Another question I have is how would I go about having my top off res always open and supplying water to my system? I know how it works mechanically, but how do I manage nutrients? Do I mix nutes in top off res and maintain to a certain PPM level. Or is it not worth it and it's better to just drain the system once a week and manually top off/mix nutes?

Any opinions and suggestions are very much welcome!!

I've updated my original buy list, the new stuff I'm purchasing is in the 2020 UPGRADES sheet, you can check it out here: https://bit.ly/32FKjoJ

Some shots of the design:

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J232

Well-Known Member
Pumping water and only having one return line makes me nervous. How big were your DWC sites? How did that run go?
 

rkymtnman

Well-Known Member
wow, quite thorough planning

i'd go with 2 pumps, not 1. 1 fails and the whole system is kaput. 2 pumps and at least 1 system runs and you could temporarily tee them together and still run all 8

if you build it, they will grow.
 

guabasa

Member
Pumping water and only having one return line makes me nervous. How big were your DWC sites? How did that run go?
Return line would be 3 inches. What would the alternative be? A second return line? An emergency drain system?

My DWC sites were 14 gallons each, it was my first run and it went much better than I thought it would. No issues at all except the pain in the ass it was to drain and refill the totes each week. Got around 350 grams dry.
 

guabasa

Member
wow, quite thorough planning

i'd go with 2 pumps, not 1. 1 fails and the whole system is kaput. 2 pumps and at least 1 system runs and you could temporarily tee them together and still run all 8

if you build it, they will grow.
Makes tons of sense, I was planning on buying 2 pumps and keep one as a backup. Do you think that would work? Or would you still run each tent with a separate pump?
 

J232

Well-Known Member
Return line would be 3 inches. What would the alternative be? A second return line? An emergency drain system?

My DWC sites were 14 gallons each, it was my first run and it went much better than I thought it would. No issues at all except the pain in the ass it was to drain and refill the totes each week. Got around 350 grams dry.
Nothing wrong with single, I know there are kits like that and guys do it. I would run a loop on both sets of 4 myself, better flow, a second path of flow when that monster root ball starts getting sucked into the return.
 

rkymtnman

Well-Known Member
Makes tons of sense, I was planning on buying 2 pumps and keep one as a backup. Do you think that would work? Or would you still run each tent with a separate pump?
i'd have 1 pump per tent. then if you want to stagger your harvest, have 2 different strains or something like that you have a bit more freedom. that's just me though. depends on your funds too.
 

J232

Well-Known Member
i'd have 1 pump per tent. then if you want to stagger your harvest, have 2 different strains or something like that you have a bit more freedom. that's just me though. depends on your funds too.
Even just focus on one tent and then clone it, if you build it all and somethings not performing for you or you want to change it, it’s x2. I made multiple changes after one run and it would of sucked to do a double change up.

OP I didn’t look at the whole parts list but how are you going to control water temp? I don’t see anything in the pics.
 

guabasa

Member
i'd have 1 pump per tent. then if you want to stagger your harvest, have 2 different strains or something like that you have a bit more freedom. that's just me though. depends on your funds too.
Awesome, thanks for your input. What GPH pump would you go with for 4 sites + control?
 

guabasa

Member
Even just focus on one tent and then clone it, if you build it all and somethings not performing for you or you want to change it, it’s x2. I made multiple changes after one run and it would of sucked to do a double change up.

OP I didn’t look at the whole parts list but how are you going to control water temp? I don’t see anything in the pics.
Definitely building one tent first, expanding to a second tent is at least 6 months away. Not planning on using a chiller for now. First run went great with just the A/C in the room, it's on 24/7.

Any recommendations for pump size?
 

rkymtnman

Well-Known Member
Awesome, thanks for your input. What GPH pump would you go with for 4 sites + control?
i think (without proof of course) that most people oversize their pumps. especially if you have a waterfall at each site.
just try to guesstimate the entire system volume and find something close.
 

rkymtnman

Well-Known Member
sorry. ... close to maybe triple your volume? 100 gallons a 300gph pump should be fine i think at least. others might say buy the biggest pump or close to the biggest.
 

Drop That Sound

Well-Known Member
500-1000GPH. I only say 1000 because sometimes you need a bigger pump to push through smaller waterfall feed manifolds. With a straight under current rdwc, assuming the return lines are 2" or bigger, a 500gph flows great through a 4 site system.
 

Sdh777

Well-Known Member
Love the designs and the work you put into this!
I have a similar RDWC waterfall set up with 4 grow pod (buckets) systems in a 4 x 4 tent. I have 3 RDWC systems running, each in separate tents with separate reservoirs and 1000gph pumps for each RDWC. I also have a large water tank that auto-fills each system, but that’s just pH water with Bennies and a small pump for circulation. I do it this way for 3 reasons.
1. I have a perpetual grow & stage each grow 4-6 weeks a part so I have smaller harvests to manage, but more frequent.
2. If you run into issues like nute lock, pythium, bud rot or a half dozen other issues that can destroy your crop, which can happen to the best of us, it’s now isolated to just one crop & far less painful when it happens.
3. I often use the 3rd tent to make feminized seeds and create my own hybrid strains.

Good luck and be sure to show us the finished product and a grow Journal.
 
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