Looking for opinions on my RDWC system design

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Hi everyone! I'm coming back for my second grow and have decided to move from DWC to RDWC. So after lots of research I've completed my design in sketchup and am getting ready to start purchasing everything. Before I do that, I was looking for some opinions on the system design and some of the components.


Quick rundown of the system:

It's a waterfall system (feed lines go into the top of the buckets) with 3/4" feed lines and 3" return lines. Feed lines will be black PVC and return lines will be black ABS. The feed lines will be aerated using Flow Rite PowerStream Nozzle Aerators. No plans on using air stones or air pumps.

RO unit will be connected to an outdoor hose faucet which I've installed in my bathroom shower, from there it will fill up a 150 gallon top off res which will be connected to the control bucket with 3/4" PVC pipe, it will operate manually with a true union ball valve I need to open to fill up the system with 0 ppm RO water once a week. This will be gravity fed and will have a float valve to automatically shut off the RO unit.

Inside the tents our plant sites will be elevated to 8.5 inches, the control bucket will be elevated to 4 inches.

The control bucket will have a hole in the bottom which will be piped directly to the pump. I'm thinking about a Hydor 1600GPH pump, will this be enough for 8 plant sites, 13 gallons each? Important to mention is I will be starting with only one tent, so 4 plant sites + control bucket at the beginning, planning to double the system later on but would like to purchase a big enough pump right from the start. The Hydor Seltz D pumps have a controllable speed feature with 6 settings you can choose from, for example, the 500GPH pump can be set to: 83 gph, 167 gph, 250 gph, 333 gph, 417 gph and 500 gph. They have 500, 750, 1000, 1600, 2400 and 3600gph models. Which one would you choose for a 4 and 8 plant system? Considering they can be dialed in.

Coming out of the pump there will be a pvc manifold with 4 true union ball valves. One goes to 4 sites in one tent, another goes to the second tent, another goes back to the control bucket for aeration and the 4th will be a drain line which goes directly to the tub in the bathroom. Idea is that when I need to drain the system I open the drain line and close the other three valves and it drains the entire system.

All piping will have pvc unions in key spots so I can easily dissasemble the entire system if need be, without having to cut and throw out a bunch of pipe.

Another question I have is how would I go about having my top off res always open and supplying water to my system? I know how it works mechanically, but how do I manage nutrients? Do I mix nutes in top off res and maintain to a certain PPM level. Or is it not worth it and it's better to just drain the system once a week and manually top off/mix nutes?

Any opinions and suggestions are very much welcome!!

I've updated my original buy list, the new stuff I'm purchasing is in the 2020 UPGRADES sheet, you can check it out here: https://bit.ly/32FKjoJ

I attached some more shots of the design.


I don't see the spacing measurements between plant containers? Make sure to allow for at least 40 inch centers....or more if your growing large plants.

You don't want the plants growing into each other during flowering.

Veg system doesn't need the spacing but flowering system needs plenty of space between plant containers.

Looks good!
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why do you want to go complicated? if you are doing it for fun and research I can understand that but it will not do anything more that a basic hand or drip feed system. those type of system were mean4 for a larger version of NFT ( nutrient film technique) the added water was meant to be a buffer/backup water system in case pump stops and the no planting medium is self explanatory. the same for aeroponics . a serious downside is that because it is so dynamic with so much water action the water can heat up very fast increase humidity very fast. if you have to add lots of aeriation variation pumps then it really defeats the purpose. the point of dwc is no moving parts or very little ,like NFT which each row is watered with just one tube .
as far as setup it is hard to say. it looks very complicated and lots of hard work
. I look forward to seeing your progression . the more reservoir to plant capacity the better your buffer capacity. ph can drop fast as there is a carbonic acid reaction that can happen with lots of water air interaction. carbonic acid is fo3med in a reaction with atmospheric co2 causing sudden ph drop .. it is very common . I have grown for 30 yrs and have always been heavy on experimentation. built and ran every system u could think of . some we just designed our selves . if it's one thing we learned is KIS method . Keep it simple. if you would like I can give you my formulas to make your own feed solutions. a little more investment on buying 25 kg initial chemicals such as calcium nitrate ( 70$ 25 kg ) but once you buy all 6 your need to can make 200 liters of 100 to 1 concentrate for 100$ ? ish ? . I see 4 liters going for 50 to 70$ .I more tidbit is that in water systems anions will be favored. so sulphur, nitrate in anionic form ( calcium nitrate as opposed to nitrogen sulphate) . Positive particles like calcium ( cations ) are taken up by soil particles interactions and anions ( sulphate or phosphate) are taken up through the solution. you can increase the absorption of certain nutrients ( cations) just by using a medium ( promix or ? ) over water . that also means that cations may need to be slightly increased to offset that. will put a post with this .What I can also do is recommend one of the best and most complete books on the subject is HYDROPONIC FOOD PRODUCTION by Dr Howard M Resh .
very accessible reading by everyone . good luck and look forward to seeing your progression .

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