RDWC design feasibility questions

Been doing a ton of research on hydro setups, but I'm not sure I've been going in the right direction or just down the rabbit hole. I'm trying to make a low-maintenance system for a small 2-plant autoflower grow w/ ScOG in a rather small 2.5x2.5 tent using 150w LED full spectrum lighting. My main question is whether a gravity return line will be sufficient for water flow rate?

I know most RDWC setups (waterfall?) have the water input coming in at the top of the bucket and return line at the bottom. However, This seems like there's a possibility the roots will grow into the return lines and clog the piping. My idea is to have water input at the bottom and return at the top, with the return hose level placed right where I want the waterline to be. Either daisy-chained serial config for maximum flow and scalability, or having the input tee'd off the pump in a parallel config to both buckets to help segregate the plants from each other. Another thought would be to have a pvc pipe return tube (maybe larger diameter) inside the buckets so I can adjust the water level as needed (higher before the roots get past the net pot and lower after they're long enough).

This will be a sterile water system, so I'm planning to drop in an aquarium UV light right next to the pump intake as well as adding a bit of h2o2 every few days. The system will also incorporate some valves where needed to allow the water to drain and allow individual bucket filling if needed. I figure this would allow a quick higher concentration h2o2 flush if needed during water changes (if needed).

Reservoir will be outside the tent to maintain the environment inside the tent. Currently have a carbon filter exhaust fan and looking into a passively filtered intake.
No water cooling planned right now since it's rather cold right now. I'm running my light and some basil sprouts inside my tent while I plan out my DWC and temps are only in the mid 60's F inside.

1. Will gravity return be sufficient for a 200/gph flow rate using 1/2" tubing in serial config? (top pic)
2. Will having separate returns w/ two 1/2" tubes will be fine in parallel config? (middle and bottom pics)
3. Can I remove the air stones from the pot and only run them in the reservoir?

Any comments/suggestions would be appreciated.
 

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Hollatchaboy

Well-Known Member
Been doing a ton of research on hydro setups, but I'm not sure I've been going in the right direction or just down the rabbit hole. I'm trying to make a low-maintenance system for a small 2-plant autoflower grow w/ ScOG in a rather small 2.5x2.5 tent using 150w LED full spectrum lighting. My main question is whether a gravity return line will be sufficient for water flow rate?

I know most RDWC setups (waterfall?) have the water input coming in at the top of the bucket and return line at the bottom. However, This seems like there's a possibility the roots will grow into the return lines and clog the piping. My idea is to have water input at the bottom and return at the top, with the return hose level placed right where I want the waterline to be. Either daisy-chained serial config for maximum flow and scalability, or having the input tee'd off the pump in a parallel config to both buckets to help segregate the plants from each other. Another thought would be to have a pvc pipe return tube (maybe larger diameter) inside the buckets so I can adjust the water level as needed (higher before the roots get past the net pot and lower after they're long enough).

This will be a sterile water system, so I'm planning to drop in an aquarium UV light right next to the pump intake as well as adding a bit of h2o2 every few days. The system will also incorporate some valves where needed to allow the water to drain and allow individual bucket filling if needed. I figure this would allow a quick higher concentration h2o2 flush if needed during water changes (if needed).

Reservoir will be outside the tent to maintain the environment inside the tent. Currently have a carbon filter exhaust fan and looking into a passively filtered intake.
No water cooling planned right now since it's rather cold right now. I'm running my light and some basil sprouts inside my tent while I plan out my DWC and temps are only in the mid 60's F inside.

1. Will gravity return be sufficient for a 200/gph flow rate using 1/2" tubing in serial config? (top pic)
2. Will having separate returns w/ two 1/2" tubes will be fine in parallel config? (middle and bottom pics)
3. Can I remove the air stones from the pot and only run them in the reservoir?

Any comments/suggestions would be appreciated.
I used 1 3/4" pvc. Something like this....
 

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Hollatchaboy

Well-Known Member
The idea is to have buckets that are more easily moveable, so a rigid pipe system won't work for me. Otherwise, a big 'ol return line will definitely solve flow issues. Perhaps I should move to a 1" return tubing.
I understand what you're saying... why not just do single dwc buckets then? I've done it and it worked good for me.
 

pahval

Well-Known Member
Hey mate, do you think h2o2 will be enough to clean reservoir from nutes? I had similar idea in mind, im curious...
 

Hollatchaboy

Well-Known Member
Hey mate, do you think h2o2 will be enough to clean reservoir from nutes? I had similar idea in mind, im curious...
I'm not exactly sure but I'm thinking h2o2 is for sterilizing anything organic. I don't believe it'll do anything to nutes.
 

pahval

Well-Known Member
Oh, thats right, i misread what op wrote... Im still hoping for a solution to clean salts in rez tank... :/
 

Hollatchaboy

Well-Known Member
Oh, thats right, i misread what op wrote... Im still hoping for a solution to clean salts in rez tank... :/
 
I understand what you're saying... why not just do single dwc buckets then? I've done it and it worked good for me.
I plan to scrog, so changing buckets will be a pain once the plants get bigger. I also like the more stable ph associated w/ a res system and the ability to easily check ph/ec/ppm without entering the tent. I'm pretty much doing everything I can to prevent problems in the water and grow environment, and hopefully keep a steady water level in the pots even if the res fluctuates. Ideally, I'll be able to leave it alone for a weekend at a time if needed.

According to what I've been reading, H2O2 is low doses is fine for adding O2 to the water as well as for a sterile grow. I won't be using any bennes. Using this as a guide: https://www.angelfire.com/cantina/fourtwenty/articles/h2o2.htm

Oh, thats right, i misread what op wrote... Im still hoping for a solution to clean salts in rez tank... :/
You mean to prevent buildup during a grow? I've never tried it (this is my first hydro grow), but I've read the UC Roots can help. I've also read that UC Roots is basically a very dilute Hypochlorous acid solution, aka bleach, but sold at a ridiculous premium. I won't be utilizing anything like that since I hope the H2O2 and UV sanitizer will be sufficient.
 

Hollatchaboy

Well-Known Member
I plan to scrog, so changing buckets will be a pain once the plants get bigger. I also like the more stable ph associated w/ a res system and the ability to easily check ph/ec/ppm without entering the tent. I'm pretty much doing everything I can to prevent problems in the water and grow environment, and hopefully keep a steady water level in the pots even if the res fluctuates. Ideally, I'll be able to leave it alone for a weekend at a time if needed.

According to what I've been reading, H2O2 is low doses is fine for adding O2 to the water as well as for a sterile grow. I won't be using any bennes. Using this as a guide: https://www.angelfire.com/cantina/fourtwenty/articles/h2o2.htm



You mean to prevent buildup during a grow? I've never tried it (this is my first hydro grow), but I've read the UC Roots can help. I've also read that UC Roots is basically a very dilute Hypochlorous acid solution, aka bleach, but sold at a ridiculous premium. I won't be utilizing anything like that since I hope the H2O2 and UV sanitizer will be sufficient.
Ok i hear ya man. It does make things easier, convenient, and more versatile. That small of tubing though your asking for a clog. I'm trying to think of a way you can prevent that.
 
Ok i hear ya man. It does make things easier, convenient, and more versatile. That small of tubing though your asking for a clog. I'm trying to think of a way you can prevent that.
I decided to change over to 3/4" tubing for the return line and use option 3 in my pic. 1" would be nice but flexible 1" opaque tubing is hard to find and expensive. I'm using another 5g bucket as the res for now, and putting all of that inside a larger 27gal casa depot bin to keep noise to a minimum. Using a rain barrel valved bulkhead as the return tap with pvc barbed fittings to connect to a 3/4" black pond pipe and an elbow on the inside to connect to (maybe) a 3/4" sch40 pvc pipe for water level control.

Maybe I'll even look into using a semi-enclosed "cage" to put the submersible pump under so that I can pipe the drain tube to it and create some semi-suction for the drain side.

Feels like I'm overengineering this, but hoping it'll create a nice low-maintenance setup that'll allow me to get away for a few days w/o worry. :D
 

myke

Well-Known Member
I just use simple 1 1/4” bulkheads. 5 gallon pails and flexible hose. Top feed. Drain on the bottom. Air stone,small air and water pump. Never have root issues going to the drain. Keep water level high the air stone pushes roots up.
feed lines come from the res. I use 1/2”no possible leaks then when there in the res.
 

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