RDWC return line question

Hey guys! Its been awhile since I've posted! but I've been reading into RDWC and building my own set up.


so I'm building a 4 5 gallon bucket system.
with a 5 gallon control bucket.
using 1/2" tubing.
My question is the return lines back to the controller bucket, everywhere I've read says make them the same length to each bucket. Why do they have to be the same length? for flow back to prevent flooding? If thats why can I just add valves to the lines that send water to slow the flow on the buckets that are further away from the control? And I'm planning on adding a overflow line as well. or is there some other reason why they need to be the same length? I know I can hook them all together, whats the advantages/disadvantages to this?

Ive been searching for info for 3 days on this and cannot seem to find anything.

Any info will help!

DIY I have been following. http://www.cannaversity.com/cannaversity/article.php?id=097

No one? ):

+rep for helpful answers

it's a physics thing, same length ensures equality in recirculation via gravity. as long as you don't go to extremes, you can be a couple of feet off from perfect. another thing to consider is rate of return vs rate of drain. if you pump faster than the system can replace, you'll get overfills and spillage. hope this helps, i ran rdwc twice and moved to something else. good luck!

might also want to consider an emergency overflow drain line. helps if you're in the trial and error stage...

Roots clog the 1/2" tube easy so overflow line is a must if float topping from large source.

I like using 3/4" tube for return and 1/2" for overflow.

thats a pretty good write up on how to make a RDWC set up ... book marked it maybe ill try an build something like that in the future

catofcuriosity said:

it's a physics thing, same length ensures equality in recirculation via gravity. as long as you don't go to extremes, you can be a couple of feet off from perfect. another thing to consider is rate of return vs rate of drain. if you pump faster than the system can replace, you'll get overfills and spillage. hope this helps, i ran rdwc twice and moved to something else. good luck!

Click to expand...

thanks for the reply! Thats what I figured it was. just wanted to be sure. I tried some nylon hose.. but the stuff it too thick and doesn't want to stay the right shape for me. it keep trying to roll back up. but i was able to get it to kind of stay for me to test it. I was getting leaks from almost all the grommets I used 5/8 size grommets and 1/2 fittings because they had nothing else.

but the flow to all the buckets was even. But I have decide to go 1" or 3/4" PVC on the return lines, like what was said in another post. and 1/2" on the sending lines. the parts for PVC seem more available locally than that I'm trying with this nylon hose. wasted some money.. but Trial and error, right?

but I think I have figured most of it out. Just need to draw out the new plans. I can still use some of the buckets I have. Just need to get a tool to drill the holes bigger and some new grommets and we should be in business. if you guys have any other tips/ideas I'm more than open for ideas.

SnapsProvolone said:

Roots clog the 1/2" tube easy so overflow line is a must if float topping from large source.

I like using 3/4" tube for return and 1/2" for overflow.

Click to expand...

Thank you for the reply! I am planning on an over flow line. I read in other posts how its almost a must. but I am planning 1/2" on that as well.


I will share some pictures once i get it up and working. and ill probably do a write up to explain how the system works for any newbies that may want to try RDWC.

Use a step bit to enlarge holes.

General Hydroponics grommets work well.

SnapsProvolone said:

Use a step bit to enlarge holes.

General Hydroponics grommets work well.

Click to expand...

ohh I never thought of a step bit
What size of step bit? That is where I always run into problems. Because grommets never say their all their diameters. :/

Do you think 1" on the return line is overkill?
So if I go for something like, http://www.amazon.com/Grommet-Connectors-General-Hydroponics-HGGR75/dp/B008UFAI9K
How big should I drill the hole?

For the grommets I have I drill 11/16" for the 1/2" barb grommet and I drill 13/16" for 3/4".

I recommend a swivel head deburring tool to make fast cleanup of the lip left on inside by bit.

for RETURN lines unless there is a major restriction in hose physics actually says it doesn't matter the length. Water will always level out.

SnapsProvolone said:

For the grommets I have I drill 11/16" for the 1/2" barb grommet and I drill 13/16" for 3/4".

I recommend a swivel head deburring tool to make fast cleanup of the lip left on inside by bit.

Click to expand...

Awesome! I got a Step bit from a friend. I just need to go pick up the PVC and Im just going to connect all the buckets together. something like this: https://www.rollitup.org/dwc-bubbleponics/497270-how-rdwc-ucdwc-diy-advanced.html

jijiandfarmgang said:

for RETURN lines unless there is a major restriction in hose physics actually says it doesn't matter the length. Water will always level out.

Click to expand...

Thats why I was confused. but I think the new way will be a little bit easier and possibly more efficient.

Yeah, thats an undercurrent style setup. I was gonna say, pretty much all rdwc use a trunk and branch style return, not home run setup anyways.

But if you wanna get technical its going to follow the path of least resistance. For the feed lines the buckets nearest the pump are gonna get more water than the rear. Don't really think it would matter....unless you went with a huge feed line.

Correct ^^^^

jijiandfarmgang said:

Yeah, thats an undercurrent style setup. I was gonna say, pretty much all rdwc use a trunk and branch style return, not home run setup anyways.

But if you wanna get technical its going to follow the path of least resistance. For the feed lines the buckets nearest the pump are gonna get more water than the rear. Don't really think it would matter....unless you went with a huge feed line.

Click to expand...

Im not planning on going for a huge feed line, thinking 1/2" Im thinking of going with a Waterfall type system? Do you think that would be best? or any input on that?

I was just saying that to cover all bases. I'm sure 1/2 will be fine.

I'm working on a waterfall type setup myself. From reading, what I can gather is that reaching 100 percent dissolved oxygen is pretty easy. But something about slight root agitation/water fall seems to accelerate growth. YMMV

- Jiji

So I got it all set up. I still got some small things to do. but its working, The over flow line is the last major thing and its all set and ready to rock.
I feel its a very clean set up. Im sure ill make changes after a grow, but we will see how it works! I'm excited.
Here are some pictures.
No idea why the site rotated upside down...





you guys have any good ways to make the over flow lines?

And... Is the control bucket supposed to have less water than the other buckets? I put in all the water, and the Controller has less, buit the others are all even.
it seems normal to me because of the pump pumping the water. but I just wanna be sure

man those feed lines and return lines are pretty small, i suppose it should be ok tho if ur using air stones, and i had 0 probs with a staggered bucket set up this one here....





as flow rate will be slow in those lines id consider putting a outles in the brain bucket like so to get some more dissolved oxygen to those babies. good luck witht he system mate and any help needed drop me a PM

sqydro said:

man those feed lines and return lines are pretty small, i suppose it should be ok tho if ur using air stones, and i had 0 probs with a staggered bucket set up this one here....





as flow rate will be slow in those lines id consider putting a outles in the brain bucket like so to get some more dissolved oxygen to those babies. good luck witht he system mate and any help needed drop me a PM

Click to expand...

Thank you for the pictures!
Yea and I wil be using airstones with a commercial air pump. so im not worried about the water flow keeping air in the system.

and like yours i plan to wrap in the foil tape.

And can you explain the dissolved oxygen to me?