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Where can I find info on RDWC?

Slinks

Well-Known Member
So ive found lots of how I built my rdwc system plan info but not much about the science... What I want to know is the science behind pipe sizes, bucket sizes, benefits of epicentre, length of pipe in relation to flow etc. I need more technical info rather than just plans so I can look at building my own system from ground up. Can anyone point me in right direction???
 

Slinks

Well-Known Member
My thinking is I'm going to convert my Wilma into a hybrid dripper/ rdwc with the Wilma res as a single tank/bucket. Its 70litres so should be more than enough space for 4 plants. Is there a good reason for the control bucket? Is it more than just water movement at play here? why not just recirculate the water with a pump and pipes?
 

ondercuver

Active Member
I can't help you with actual science .. some formulas you can get from google , but I doubt they will help.

The control bucket helps with mixing the nutes , measuring ph/ec , maybe cooling a bit and volume of water , more volume more stable the solution.

about pipe size ... return should be as big as you can afford , there's no pipe too big ... feed doesn't matter, my system uses a garden hose with a small aquarium pump 1400l/h ... takes some time to mix the nutes every week ...
 

Slinks

Well-Known Member
Ok so there's no ratio between pipe size n container.. I got a 70l res n dropper system I'm gonna turn into a 4 plant single unit dwc first but I want to keep water moving right so just adding a single control bucket say 12 litre and 2 large returns and 1 smaller flow pipe with pump?
 

Scrogdawg

Well-Known Member
Don't go smaller than 1.5" on the return side. It has nothing to do with flow but will keep the roots from clogging the pipe and flooding your system. I'm running 3/4" on the pump side using a 550 gph submersible pump.
 
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Dr Fish

Well-Known Member
Any system that circulates water from a reservoir is in fact a rdwc... The speed and rate of flow is a personal preference.. That's why it's so hard to find what you could call exact science.. Each system has its own science... One man's treasure, is another man's garbage.. Maybe not garbage, i prefer to call it personal preference..
I use only air to move water to and from the reservoir... For me that avoids adding heat from a submersible water pump... Not only that, the flow rate is a paltry 6 gal an hour...
I prefer GH waterfarms for my rdwc... I'm lazy, they're simple, a match made in heaven..
Drop by my mixed hydro thread..
 

iNeedMeds

Active Member
A 4 bucket system is easy to build. You can build them in series circuit bucket to bucket, or as a parallel circuit where every bucket is fed by and returns to the reservoir. You don't need crazy amounts of circulation. If you exchange the nutrients 1-2 times an hour, it's enough to homogenize your nutrients. 4 buckets, 4 gallons per bucket (1gallon for net pot space) 16-32 gallon/h. Get double or triple this amount, and use a valve to determine flow. Some pumps are variable.

If you're running in series, the line from your pump to the first bucket can be 1/2". From bucket to bucket, the largest practical size will get you the most equal levels between buckets. The faster you want it to recirculate the larger the hose size. 1" should be plenty, and 1/2" is probably enough. To prevent roots from plugging the drain side of the bucket, glue small net pots over the drain holes on the inside, and cover them with landscape fabric that allows water to flow, but keeps the roots out. Use epoxy, or something that isn't toxic once cured. Sand plastic to promote adhesion. Personally, I would build an airlift pump to provide head pressure, as it won't heat up your nutrients, and aerates the water. Design for some overflow, and pipe it to the bottom of your control bucket to keep it aerated. You need an air stone anyways, so might as well kill two birds while stoned, or something to that affect.

With a parallel circuit, each bucket gets a feed line and drain line that connect to trunk lines. If you're smart, set up your system so that the holes for the inlet and outlet from your buckets are level with the water line you wish to achieve. Run the inlet to the bottom, and drain from the water line. This will skim any crap on the surface of solution, and you can drain the system by using the inlet as a siphon. Just make sure you have a back-up valve or keep the control bucket at the same level with a float valve, or buckets will drain to the control bucket. In this configuration, the buckets will top themselves up automatically if the pump fails.

I would go with the parallel circuit with the siphon feature. I like to use quick disconnects on hoses so that buckets can be removed easily for cleaning.
 

Stltoed

Well-Known Member
My system is about 50 gallons. I use 2 inch bulkheads and tubing between the tubs and res. Scrog dawg is absolutey right about tube dia. But I've never had roots anywhere near my contracting lines since they are at the bottom of the tank. My roots tend to hangout at the top of the tub My return line is from a submerged water pump in the farthest tub. This line is half inch. It returns to the res of course. The pump is just about 500gph if memory serves. My air is overdone. I use a 80 liter linear pump with half inch leads to 2 12 inch diffusers, 1 per tub. I like a lot of air because it's harder for pathogens to get a foothold, it keeps fresh nutrients at the roots and helps keep them clean. When im transitioning young plants to the RDWC the aggressive air bubbles popping keep the roots in the air, not in the nutrients yet, damp. I highly recommend a reservoir. It's a true benefit when adding nutes, test the water, cool the water, and even keep the water at level by using an auto fill valve... my personal favorite feature. other than my HannaGroline meter. I'm afraid i have no science to prove any of this, but i just harvested 2 plants one was 10.8 the other was 16.2oz. I can live with that
 
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