Your thoughts on my DIY RDWC hose/pump sizes and plumbing methods pls

I've been doing research and reading guides on RDWC, but I've come across some inconsistencies that I'm hoping to clear up here. Basically to do with hose and pump sizes and plumbing methods. I want to avoid unequal flow rates(drain and fill) among my buckets, as well as them overflowing due to too big a pump or too small return lines.

I've heard a few people say 1/2" return lines are too small, and caused their buckets to overflow. I've also heard people complain about uneven nutrient distribution because they plumbed it wrong.

I've seen some videos online where people have a 10 or so line manifold thing that connects to the water pump(sticking up out of rez), and gives equal flow out of each line. I can't seem to find those online, so if anyone could help me find those, that would be sweet. If I can't get one of those, then this is what I'm thinking of doing;

Water pump will feed a 3/4" hose out(my supply manifold) which will have T's connecting to 1/2" lines running to buckets. I'm hoping the 3/4" manifold will hold higher volume, causing all the 1/2" lines to flow the same amount, even to the buckets farthest from the pump? How big should the pump be for that?

Then I'm thinking the return lines should be 3/4" feeding into a 1" return manifold? Will gravity cause them all to drain equal, even the buckets farthest from the rez?

Or should I put the pump on the return lines, and let gravity feed the supply? That might create a more even flow?

All thoughts and ideas wanted! Thanks guys

I'll start from the bottom and work up. No no no no you do NOT put the pump on the return line. The pump goes for supply, gravity for return. The supply line empties out near the top of the bucket, gravity will not take water up hill.

The return lines should be 3/4". If you put your system on flat ground (as long as you do everything else right) gravity will cause them to have an almost identical water level, regardless of how far from the Epicenter. The funny thing about water is it seeks it's own level.

Hopefully I explained that well enough, but probably not. I will try and get pictures up later, as I am actually in the process of building an RDWC.


Chances are the supply line will be 1/2". That is really up to the outlet on your pump. I use a 500GPH Mag-Drive Pump (it sits outside the water, so it does not create heat build up like a sub pump. Those manifolds you've seen on the internet are probably homemade. You lay a 1/2" manifold down, on top of or directly next to your return manifold (the 3/4" tube that is being gravity fed back to epicenter). At the end of each row you cap the 1/2" tube. Everywhere there is a plant, poke a 1/8" hole through the 1/2" supply line (I used a meat thermometer since it was right there in my cloner. Using pliers stick a 1/4" straight barb through the little hole. Then hook up the tube to that barb, and connect it to the barb that should already be attached to your bucket. Repeat for each plant and you now have your supply manifold.

Oh and make sure on your 3/4" Ebb and Flow outlet fittings for your return lines have the little screens they make over them. They are specifically made for the ebb and flow fittings, and they really help prevent clogs.

Awesome, thanks for the tips!

Just curious tho, why no pump on return? That's how the Undercurrent does it, and I think it gives better flow, plus the pump can be out of the rez. At least that's what I make of it, but this is my first time so that's why I'm here asking what may be dumb questions. Sorry if they are and thanks for taking the time to help me out.

Sorry for the slow response, I've been super busy, my internet is crap until Wed when they fix it, and RIU went out of their way to make their website much worse by getting rid of the last 5 posts from MyRollitup. I suppose you could put a pump on the return instead of the feed, but only one pump is necessary, let gravity do the rest. I know the UC system uses a pump on the return, and let gravity refill. But most traditional RDWC I've seen use the pump on the feed, and gravity on the return. So I guess it depends on what you're trying to do. But when you were saying 1/2", 3/4" I was thinking more along the lines of something like this: https://www.icmag.com/ic/showthread.php?t=26343&page=1/
If you're trying to mimic the UC system they use 2" or 3" PVC in uniseals, not 1/2" or 3/4" vinyl tube.

hey I repped u smurf and it jumped u up a bar, LOL

Sweet, I was wondering if I was ever going to go up a bar. Man, I've been so crazy busy. I scraped my old system and threw together a completely different RDWC in 48 hours. Then I had to cut down a dirt crop, and I've been trimming ever since. Bout to take my first shower in 2 days and get back to trimming. The exciting life of a farmer.

Edit: Kind of off subject but speaking of trimming, I do not understand the logistics of trimming crops of 5, 10, 50, 100+ lbs. I've seen people run perpetuals with much more light than I, how can all that be trimmed. It takes me and 2 or 3 other people 4 days to trim just under 2 lbs (working 10hrs a day). I feel like I'm doing something wrong.