Continuing the discussion from First hydro setup and grow:
Tried to move topic from grow room design to the diary… best I could seem to do. Will post follow ups here 
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Hey all, first hydro setup for me. I can only grow 1 plant in a 5 gallon pail in my grow tent. Was thinking of a setup that would incorporate 2 pails. 1 inside the tent and 1 outside that would circulate water to the tent. My plan is to use 1” tubing off the bottom of the tent pail and have it run to the top of the outside pail. Then off the bottom of the outside pail would also be 1” tubing that is gravity fed to the tent pail. (Let me know if I lost you) lol
I would have air stones in each bucket of course but figure the outside pail would be more convenient for feeding/testing and whatnot… Also I thought tubing would work best as it’s flexible and don’t want to hard pipe anything. please let me know what you think.
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+1 for black vinyl tubing, it’s super easy to work with.
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If you are going to do gravity feed, then the “return” hose/pipe needs to be much larger than the line with the pump in it.
You are going to need a pump between the buckets, and you can use 1" hose for the pump line. However, gravity alone will not provide the same pressure or flow rate that your pump will - by a large margin.
So, if you are relying on gravity to move water back from one bucket to the other, that line needs to be a lot bigger than the pump line, or it wont keep up, and the bucket you’re pumping into will over flow. It wont empty as fast as its filling.
I dont remember the math at the moment, but the pipe sizes will be dependent on the gallons/hour of the pump, and how tall the buckets are. Its been a while since I looked into RDWC, but I think most guys use 3/4" for the pump side lines, and at least 2" for the returns.
Plus, you dont want the return line to exit or enter the bucket at the top. It needs to be at the bottom of both buckets. The higher it is, the less pressure you will have from gravity, which will reduce the flow rate.
Its best to put the pump lines at the top if you want a waterfall effect.
You will also want to add a float switch to cut the pump off just in case.
You also need to decide on the type of pump you’re going to use and how to do the plumbing.
The less expensive option is a submersible aquarium pump. These work fine, and are relatively cheap and easy to repair. The downside is they heat the water up. You want to keep your water temps at or below 70F if at all possible.
An in-line pump will not heat the water up nearly as much. but they tend to be a lot more $$.
I chose a pump that is submersible, but also works as an in-line pump. It comes with the parts to use it either way and isnt all that $$…
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Thanks for the input @anon32470837 much appreciated.
Maybe I’ll do 1” gravity feed and 1”x1/2” reducer for the return line. I don’t want to go smaller then 1” outlets on the buckets incase the roots try to grow in and clog them. (Maybe a screen would be necessary)
Was looking at a 290gph pump but thinking of putting a dimmer switch on to make it variable speed. Really only want 50-100 gph if that… I seen a cpu fan that was 43gph that I might look more into.
Thanks again
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You will want a fairly high flow rate - it makes for much better oxygen saturation/aeration. I doubt 1/2 to 1" will be nearly enough size difference unless the flow rate is very low. If you’re planning that low a flow rate, Id just skip the pumps and do straight DWC with no re-circulation.
Also, screens dont stop roots - unless they are fine enough mesh to almost stop the water flow. They just clog up faster when the roots get there. You need to just plan on being able to get in to clean them out periodically. 
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I might just try it and see what happens. The air stones should created lots of air in both buckets. The nice thing about growing is the trail and error aspect. Definitely like the mad scientist part of it lol
Won’t have all the material till the end of the month anyway. Seeds are on the way from GYO Seedbank. (Not sure how reputable they are tho) 5 pack of powerbud autos.
I’ll do a little diary once things get going
Daddywronglegs
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Following up with what Larry has noted:
With a single 5 gallon grow bucket, the noted 50-100gph should be plenty I’d think. Probably not much head to deal with unless the outlet of the pump is necked down. The 1.0-1.5 inch gravity return with a 1 inch inlet does seem a bit small, though. You’ll likely see the running level in the growth bucket end-up somewhat higher than the level in the reservoir.
If you have the option, also consider a DC controllable pump. There are some relatively inexpensive (e.g. chinesium - Jebao) versions on Amazon. And, somewhat more expensive versions there too. You can control the flow rate on those to some extent in the event you overwhelm the return flow. Alternatively, you could always restrict/split the pump outflow with the downside being the potential for cavitation (normally you’d want to avoid that).
The chief complaint I’ve seen from others that do something similar (a small return diameter) is that the roots end up reducing the return flow rate eventually overflowing the grow bucket and sucking the reservoir dry. But if you regularly pay attention, I’d think such a scenario can be manageable (just more work). But, idk, could work fine since the DIY stuff is always unique in one way or another.
Yeap, the DIY mantra. Let us know how things progress. Very interesting.
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I use 1" return lines hooked up to containers with 1" bulkhead fittings.
The supply lines consist of a 1" manifold to equalize pressure with half inch runouts that elbow down and create a waterfall.
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@SquirtleSquad great looking setup for a few plants! Was there some trail and error with that or is that how it was planned from the get go?
Props +++
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Yup, that works because you have the manifold splitting the pump output between EIGHT different buckets, as opposed to a single bucket. Plus, you neck down the pipe size, plus you have extra elbows, etc.
All that reduces the effective pump output to each bucket. In effect, you have more than a ten to one size difference between the effective in and out pipe sizes.
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The only addition I made was clamps. The polypropylene piping I bought originally needed petroleum jelly to fit over the fittings. Then I didn’t have enough so I bought more and they must have switch suppliers cause this new junk slides over so easily that if you so much as look at it wrong it leaks
Other than that system is how I envisioned it.
I did have help with this system from a friend over at RIU named ttystikk. He used these systems and they are much cheaper and IMO better than the UC pieces of crap.
Cavitation…haven’t heard that term since fluid Dynamics class lol
Thank you
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No doubt. I also have 4 bulkheads on each tote. For a total of 24 (only 6 site, the other two are independent) outlets. Only 4 run back to control tote though.
The pump only pulls less than 2" off the control bucket when it’s running.
It is 550gph for <50gal system volume. Each tote has 6-7gal x7.
The smaller piping allows for a faster flow vs. larger piping. 1" bulkheads are also considerably less money than 2" and fuck uniseals. Bulkheads are bulletproof.
Admittedly I do have to pull roots out a few times a grow, but this is a minor inconvenience compared with pHing 6 totes everyday. Even easier with the pH doser I put in. With my 27gal tote system I rarely have to pull roots out.
It also makes chilling the water in the summer easier.
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LOL I have ignored way more than my fair share of ‘good advice’ over the years. Thats half the fun!
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It’s the internet and, when it comes to DIY, prefer to call it “commentary” that helps to get the brain juices flowing.
With so many different levers, I’m always pleasantly surprised by the amount of innovative and interesting DIY. Many times with results that end-up building on the collective knowledge. Keeps the community lively and moving forward…
Looking forward to seeing this system up and running!
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This. Bulkheads for peace of mind.
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I used Uniseals on my first ever RDWC four bucket grow and what a pain in the ass they were. I would only do bulkheads in the future.
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Put everything together today the circulation is great!
I can control the water level in each bucket with a valve I installed before the pump. (5gallons fits perfect) northern lights x big bud auto is having a sleep over in a wet paper towel tonight and rockwool has been soaking for the past 3 days… let me know what y’all think or have questions about.
I can control the water level in each bucket with a valve I installed before the pump. (5gallons fits perfect) northern lights x big bud auto is having a sleep over in a wet paper towel tonight and rockwool has been soaking for the past 3 days… let me know what y’all think or have questions about.
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