Help with DIY UnderCurrent in RDWC

Will raising the height of the reservoir change the water level of the rest of the buckets? all buckets and reservoir are 16"w x 14"d x 15"h. The reservoir is outside the tent. The piping rises 12" from the ground to the top of the piping to go inside the tent. How high do you recommend raising the reservoir? Thanks


i’m going to say YES-- what are you trying to do/prevent/etc?


It depends if you have a system piping in and out of the res. The basics of water is gravity. It will flow to the lowest point if it can.I

Pictures help if you can.


Yes the water will run down into the reservoir. Picture two buckets with hoses connecting each other at the bottom. As you fill one the other will fill to the same level. If you picked one up the water would run down the the lower one

If you’re making a recirculating DWC they’ll need to be on the same level (more or less).


I think I need to raise the reservoir because my piping goes up to enter the tent then back down. (so the res needs to be higher than that point). I will just raise the buckets some too i guess.

You can raise the pipe to get it out the tent outlet and then back down to the ground. The issue is that every time you do a res change you would have to check and make sure that pipe is purged of all air. If at any time some air (from an air stone etc) was to get in the pipe it would go to the top of the pipe where it goes out the tent and then the water would stop flowing and the bucket you are feeding the water to will overflow.


Thanks = I will raise everything above the highest point the pipe goes up to the tent

Yeah well in short it can be done but it is a little more risky and problematic. Not worth it in my books. I would cut a hole in the tent or put the control bucket inside the tent as well. You wont be able to check it without going into the tent but at least res changes and maintenance will still be a lot easier.
Like you said, all at the same level of the tent outlet is good but then you lose a little height. My system is quite different to yours. It is still RDWC and i also took the height hit for a similar reason.

will undercurrent work correctly if the feed line goes up to enter the tent since I think it supposed to feed with gravity -with my res raised higher - pipe goes down then up into tent then straight into buckets?

Yes it will be fine if the buckets are the same height as the res. And if the highest point of the pipe is the same level as the bottom of the buckets you will not have any troubles with air in the pipes stopping the water feeding to the other buckets.


heres a picture

will this cause any problems - nothing glued yet just mock up

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Yes that will cause problems. You can see from the first pic the pipe has to raise up to go through the tent outlet then it goes back down to the ground where i imagine it will then go into your control bucket/res.
If you do not want troubles then you would want to raise the buckets both inside and outside the tent so that the conduit pipe that goes from the buckets to the res outside does not raise up at all to get out of the tent.
What you have shown above is a bit hard to tell as i can not see the control/res bucket but it could get air trapped and stop flowing or the pipework going out of the tent could cause the level of the water in the buckets to change. You do not want either of those to happen.
If you want the res outside the tent and you want to use undercurrent for the return of the nutes/solution then you will need all of the pipework for the undercurrent to be at the same level. Since you have to get the pipe out of the tent and since you probably do not want to cut a hole in your tent you will need to raise all of the buckets and the res so that the bottom of the buckets and the undercurrent pipes are all at the level of the tent outlet.
If you are keen then you can have it all closer to the floor by cutting a hole in your tent close to the ground and you can buy a fitting that clamps to the tent lining and turns it into a proper tent inlet/outlet. Then it will all be on the floor level and will flow properly.
I had similar issues to you a while ago. I overcame it by completely redesigning my setup to stop using undercurrent. I now use a 50 mm bulk head in each bucket at the level i want it to drain at. So the buckets drain out of the top which is high enough to leave the tent outlet and into the top of the res outside. the issue is that i can then not drain all the buckets just from the res. That does not affect me as my buckets are huge (50L each) and i made a door on the top cover of each on so i can just drop a pump and hose into them to drain them out.


what if I raise the buckets inside the tent 6" so the pipe goes up into the tent then straight into the buckets eliminating the down ward. then raise the res/control bucket up 12" so it is higher than everything. But then the piping from the control bucket will need to go down to the floor and then up into the tent. ? thanks

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No, I think you are missing a key point here. The idea of a undercurrent is that water will always try to run downhill. So the first rule you must not break is:

All buckets MUST be at the same level as each other.

Secondly, if you want to minimise issues and chance of floods etc then the pipework for the undercurrent which connect to the bottom of all the buckets to return the water/nute/solution must all be level with the bottom of the buckets. If you go against that, you will have a flood one day. :slight_smile:
It may be confusing because i said something at the start about being able to drop the pipework below the tent outlet but that was before you posted the pictures which showed you were explaining something very different to the photos. So ignore my first comments about dropping the pipework below the tent outlet. All pipework must be level and at the tent outlet level.


Take it from someone who tried all sorts of gravity feed solutions. Then after much messing about came to the conclusion that if your buckets and pipes are not all at one level then you are risking floods and other issues.
My solution in the end was to not use gravity feed if they are not all level.


I just added edits to the top two posts, if you give them another read it may help.

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I make everything level except the piping that runs on the floor so I can walk. Maybe raise the res/control bucket a little higher for gravity insurance.

the only negative i am finding is that I won’t be able to drain the piping that is on the floor

I would not be raising the res if I were you. Don’t go against the instructions. Surely they state that they all have to be level? I imagine there would be something like that in there. As you have found out, even having the piping below the bottom level of the buckets is going to cause you trouble.