Reverse DWC

An idea I'm playing around with, curious to know if anyone has opinions on this setup.

Currently I'm using a 5 gal bucket rez gravity feeding two 5 gallon grow buckets with bubblers in the grow buckets. Works pretty good but I'm not super happy with the PH swings and it's a PITA to measure/adjust PH in the grow buckets. So I started considering going back to pumps. That way I can adjust PH in the rez.

Anyway, I start thinking about how solution level drops between waterings and how I'm wasting the rez content every week and I come up with this.

Pump nutrient solution from bottom of rez into bottom of grow buckets, gravity feed back to the rez. This way, as the water is consumed the rez level will drop while the grow buckets will not. Water level in the grow buckets will drop only if the rez get's so low the pump can't operate.

I'm considering using 1/2 line on the feed and 3/4 on the return to insure the pump doesn't overwhelm the buckets. Will still have the air stones in place. If the pump fails, circulation stops but rez will still work via gravity feed. Any other considerations? Thanks!

Sounds a lot like an RDWC system with a control rez to keep the pail's water level constant.

I use to put the bulkhead in the middle of pail then on a table,res underneath.Level was always the same no matter what the res did.

Your return lines need to be at least 2x as big as you're planning imo.
You're pretty much describing a recirculating dwc system. Plenty of us around here running them.

It is SO GOOD to see you posting, Rahz.

And is this possible? I might actually be able to share some knowledge with the one who mentored me through everything I know basically?

fragileassassin said:

Your return lines need to be at least 2x as big as you're planning imo.
You're pretty much describing a recirculating dwc system. Plenty of us around here running them.

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I agree with your comment on line size, and fair enough. In the past I've always fed the water in from the top which seems pretty common, or an inline setup which pumps the water from a rez back into the first bucket. Seems like in either case the water level between grow bucket and rez will be similar.

Airwalker16 said:

And is this possible? I might actually be able to share some knowledge with the one who mentored me through everything I know basically?

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It means building a manifold from T fittings and requires a bit more tubing than an inline setup but should work just fine. As the water level dropped in the rez the pump might become less efficient at moving water, but that's just a matter sizing the pump right.

I use waterfalls. Built a manifold that's all 3/4" until splitting to the bucket where it reduces to 1/2".
Been this way for years. Only difference is my res level is the same as every bucket is. Water returns to the res through the 2" pipe.

I'm running this right now without issues. Water fed into bottom of buckets from 1" tubing, and gravity brings it back to the rez through 1.5" pvc pipe. I use a 250gph inline pump and the water level in the buckets is constant. I fill the whole system with 25 gallons at rez change and can lose 8 gallons of water before the pump sputters, but the buckets stay the same as long as the pump is running. Roots can't clog anything up this way, which was a main reason for why I built it this way.
Is this what you're talking about? It is a RDWC, in that it recirculates, the water just flows the opposite direction through the buckets than the systems most people use.

2WorldsFrog said:

I'm running this right now without issues. Water fed into bottom of buckets from 1" tubing, and gravity brings it back to the rez through 1.5" pvc pipe. I use a 250gph inline pump and the water level in the buckets is constant. I fill the whole system with 25 gallons at rez change and can lose 8 gallons of water before the pump sputters, but the buckets stay the same as long as the pump is running. Roots can't clog anything up this way, which was a main reason for why I built it this way.
Is this what you're talking about? It is a RDWC, in that it recirculates, the water just flows the opposite direction through the buckets than the systems most people use.

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I would think once the res gets so low that suction of water is impossible, the pump would allow water to flow back from the bottom 1" feed lines into the res? Certainly if the pump ever turned off right?
Mind a few pics of the feed lines?

Yes, if the pump isn't on the water level will eventually be the same in all containers. I do have to keep at least 2" of water in the res for the pump to pull from, but that's around 8 gallons or so less than full so I really don't let it get that empty unless it's almost time for a res change.
The 4th pic from my last post is about the best I can do to show the supply lines. It's the black vinyl tubing below everything else. It's setup the same as the returns with 3 T's to balance the amount being fed to each bucket.
I do have an air stone in each bucket because I wasn't sure that only the one waterfall into the res would generate enough DO. Any thoughts on that?

2WorldsFrog said:

Yes, if the pump isn't on the water level will eventually be the same in all containers. I do have to keep at least 2" of water in the res for the pump to pull from, but that's around 8 gallons or so less than full so I really don't let it get that empty unless it's almost time for a res change.
The 4th pic from my last post is about the best I can do to show the supply lines. It's the black vinyl tubing below everything else. It's setup the same as the returns with 3 T's to balance the amount being fed to each bucket.
I do have an air stone in each bucket because I wasn't sure that only the one waterfall into the res would generate enough DO. Any thoughts on that?

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I'm never using airstones again if I can. I use a waterfall in ever bucket site.

Rahz said:

I'm considering using 1/2 line on the feed and 3/4 on the return to insure the pump doesn't overwhelm the buckets. Will still have the air stones in place. If the pump fails, circulation stops but rez will still work via gravity feed. Any other considerations? Thanks!

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I'd say that a 1/2" supply with 1"return might work, but you wouldn't want a strong pump because the water returning moves slower.

Bro 1" wasn't even remotely close to enough to keep the res full. That's why my setups got 2". Use 2" or even 3" or you'll regret it. Trust me. 1" is not even close to big enough. 2" is 4X more space.

Airwalker16 said:

Bro 1" wasn't even remotely close to enough to keep the res full. That's why my setups got 2". Use 2" or even 3" or you'll regret it. Trust me. 1" is not even close to big enough. 2" is 4X more space.

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I was quoting the op's question about what size he was going to use for his "reverse" system. Moving the water the other direction lets you use smaller lines because you don't have to worry about roots clogging anything. The most important thing to consider with that is pump size.

I completely understand why you would want bigger return lines for a waterfall system. Last time I ran that kind of setup I used 1.5" returns without a problem. I had a couple stringers find their way to the res but each plant had a large tote to itself and the pipe runs were short so idk, whatever works, works I guess. I had 2 25gal totes with a 2gal "res/control" for top-offs and ph.
I think it's really about what combinations work together.

2WorldsFrog said:

I was quoting the op's question about what size he was going to use for his "reverse" system. Moving the water the other direction lets you use smaller lines because you don't have to worry about roots clogging anything. The most important thing to consider with that is pump size.

I completely understand why you would want bigger return lines for a waterfall system. Last time I ran that kind of setup I used 1.5" returns without a problem. I had a couple stringers find their way to the res but each plant had a large tote to itself and the pipe runs were short so idk, whatever works, works I guess. I had 2 25gal totes with a 2gal "res/control" for top-offs and ph.
I think it's really about what combinations work together.

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I know buddy. That post was for @Rahz

I was thinking foliage in the res, roots in the air, upside down plant from the title. Had a sweet image in my head........

2WorldsFrog said:

I'd say that a 1/2" supply with 1"return might work, but you wouldn't want a strong pump because the water returning moves slower.

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There will be a single 1/2 inch supply and 2 or 3 returns, so I'm going to try 3/4 inch returns first and see how it goes. And yes, your system is exactly what I'm talking about. Good to see it's been put into action.

Rahz said:

There will be a single 1/2 inch supply and 2 or 3 returns, so I'm going to try 3/4 inch returns first and see how it goes. And yes, your system is exactly what I'm talking about. Good to see it's been put into action.

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Rahz, you gave me so much great advice that saved me headaches when I was learning. Please take my word and use AT LEAST 1" To start, so you'll only have to go to 1.5" when you see its not enough.