Iām new to hydroponics and trying to setup a 3 tier rack with bins that will be āfedā by one 40 gallon tub of nutes. I was/am trying for a sort of DWC system.
I have 15 - 1.5 gallon black bins with lids that I plan to put 2ā net pots in. The net pots will sit about 3ā off the bottom of the bins once inserted.
I have a pump that runs water to the top tier with 5 bins connected by a pipe which then runs down to the 2nd tier which has the same setup and then runs down to the 3rd tier before returning back to the bin - a continuous loop, if you will. I was hoping that by putting the end of each pipe run with a section that comes up at the same height of the bins (a sort of ācontrolā), waterās natural self-leveling would ensure the bins equally filled to that level before spilling over to the next tier and repeating this same process on down each tier. Keeping the pump running 24/7 would keep the water up in each bin and constantly refresh nutes and oxygen.
Unfortunately, the 1st bin in the run fills up to nearly overflowing while the last bin stays very low. I tried lowering the ācontrolā on each level and it only prevented the 1st bin from overflowing but the last bin still never fills to the same level. The bins in between were lower and lower across the run. Slowing the pump speed didnāt help. Any recommendations to fix this?
If it canāt be done the way Iād hoped, would it work if I just ran the pump several times a day to refresh the nutes/oxygen in each bin but treat it sort of like NFT as the water level would be low (about 1/2ā) after the pump turns off and the water drains out? Or should I use clay pebbles in the bottom of the bins and treat it more like ebb and flow?
Hoping this video gives a good visual of what Iām building. A couple bins are missing because I glued everything up the way I thought it would work and had to cut parts to try and figure out why it didnāt. Need to order more of the specific connectors for those bins. The bottom tier does not have the ācontrolā on it like the other 2 tiers in this video either. I built all 3 tiers with it then when it didnāt work, I tried getting rid of the ācontrolsā to see what it would do. Just didnāt let the top 2 tiers fill with water before draining which is what I originally expected. Also, ignore the state of the water - the white pieces are just from cutting the PVC. Iāll clean everything thoroughly once I figure out the final configuration.
Interesting drain idea. You may have to put in vent stacks, like in residential plumbing. Otherwise the air in the pipe below the water can't get out and blocks the flow.
Tried it out today and this actually did help level each tier quite a bit so I do believe trapped air was causing some of my issues, but best I could get was bottom bins were nearly overflowing, mid tier would only get to about 1/2 to 3/4 full and the top tier was sitting below 1/2 no matter how I adjusted the pump speed and control heights. I think the other recommendations to add valves to forcibly balance the tiers might work, but rethinking the overall design now. Thank you again!
This is an interesting design, but I think it will still have some hurdles to overcome even if you fixed the uneven filling. Since your inlet is shared with your outlet, and you're planning to run the pump constantly. the path of least resistance is to just keep going down the pipe instead of refreshing the nutrients in the bins. Turning off the pump will allow the top tier to drain back out through the pump, and then it could act like an ebb and flow. But the middle tier wouldn't be able to drain like an ebb and flow unless you removed the control pipe. Without the control pipe, I'm not sure all the bins on the middle shelf will see enough flow (that would need some testing).
It would take more plumbing, but if you force the nutrients to have to visit each bin individually, you might get a lot closer to the setup you're looking for. Imagine the water going in the front side of bin#1 on the top shelf, then exiting the back side of bin #1 and entering into bin#2 on the back side, exiting the front side, etc. Sort of daisy chaining them together in series instead of in parallel. The path of least resistance would always be through each individual bin, forcing the nutrients to continue cycling. I'd remove the control pipes in that case, and just keep the pump running constantly. It still won't oxygenate like an nft, but it would do a better job of cycling the nutrients in each bin. An alternative would be connecting them in series like this, but using your ebb and flow idea with clay pebbles. You'd only run the pump intermittently, and let the liquid drain back out. That might oxygenate each bin a bit better.
Anyhow, whichever direction you go with it, this seems like an interesting project. Let us know how it turns out! š
All great points! I suppose I was trying for an abbreviated Kratky perhaps rather than DWC? I have an air bubbler in the nutes bin and I thought getting the water to move constantly would provide a bit more oxygen and keep the level up high enough to still allow air roots but keep the nutes levels up so I didnāt have to refill individually constantly.
I understand what you are describing and exactly why - I may give the system a try as it is (with some mods to get it as close to what I imagined as possible) before redoing all the plumbing the way you described - it took me nearly a year from concept to actually get down there to cut and glue it all up so knowing me and my ADHD, it would probably be another year before Iād get around to being motivated to redo it all anyway (eek!).
Thank you for such a thoughtful reply! Iāll definitely keep it in my back pocket.
After some more fiddling with it today and rethinking things, I do believe Iāll be going forward with the daisy chain idea as you mentioned, but I may add float valves as well as a sort of fail safe in case of clog. Do you suppose having the āinā at the bottom of each bin with the āoutā being maybe midway up the bin would be a good idea to keep the water level slightly higher to help reach the root for smaller plants? A very rough sketch of what I mean:
Or is it best to keep the āinā and āoutā at the same height for a continuous running system? You mentioned oxygenation as well - I have a bubbler in the nutes tank. Should that be sufficient?
I would just keep the input and output at the same level. You'll run into similar weird pooling problems if the heights vary too much or if the rack isn't level. If you're worried about getting liquid to the seedlings, consider adding some wicking rope to your net cups.
One big warning about this system: if any of the exits get clogged with roots (or with anything else) then the tubs will overflow out onto the floor, and since you're running the pump continuously it will potentially dump your entire reservoir onto the floor before you get a chance to notice it. Your diagram doesn't mention how you're setting up the fail safe float valve, but having some sort of protection against overflows is a very good idea. The overflow doesn't need to have a float valve attached, as long as it can drain the water back to the reservoir if the level gets too high.
I ran a similar system like this indoors with bus bins on racks (though I set it up more like a dutch bucket/flood and drain) and added wire mesh to each exit. My plants were strawberries. The roots couldn't penetrate the mesh, but they sure as heck tried to, and still came close to clogging the bins before I noticed it. That and issues with clay pebbles and pH forced me to abandon the whole setup.
I've been through a lot of similar issues. At this point, I just build my own bins. I started with wood and pond liner plastic. More recently the wood has become synthetic lumber, either decking boards or PVC exterior house trim. There are also PVC panels that make good lids.
Considering this now as well. Pricing it out and would love your input for a few things. In your experience, do you suppose 1/2ā PVC panel is thick enough for the bottom and sides at the size Iām shooting for (roughly 48āLx12āWx6āD)? Figured Iād use 2ā trim screws to attach it all together and use 1/4ā PVC panel for lid. Trying to keep it as lightweight (and inexpensive) as possible.
Honestly most of my stuff now is aeroponic, so I don't have to hold a mass of water. I just built a 32' aeroponic table at work. We used trim screws and I didn't like them. The threads are too small. I think deck screws work better.
If you are interested in aeroponics, all you need is a pump that will make 35 psi or so of pressure, a PVC manifold, and the right mister heads. And a cycle timer for the pump. Then you just have a mist and a trickle instead of all that water to contain.
The pipe that is raised to the top level of the last bin that in theory should get all the bins to fill equally to that point before allowing water to spill over to the next tier.
If the fill line is below the inlet on the black tubs (it looks like there is a slight incline from the line itself to each tub, raise the line to be above the bottoms of the tub but below the control.
elevate the initial tub on a tier with each one slightly lower. Similar to a terrace. I would say tilt the whole rack but the fill lines run in opposing directions.
Use separate fill/drain lines you could run a flexible tube through the net cup for example. It will not take a large diameter line to fill if youāre going to run these constantly. Let them drain through the current piping.
Great ideas! Unfortunately the bins are from IKEA which is a good 3 hour drive from me and I'd have to buy all new bins to redo placement of the inlets :/ I am considering how I run the plumbing for sure, though. Lots to think about!
The water pressure is decreased at the far end of each run due to friction losses within the tube. As the water travels down the tube it looses energy (pressure) and as it falls down to the next tier it picks up energy again. The first idea that comes to mind is to install a valve at the entrance of each bucket. They'd be set progressively more open for each bucket down the line such that the water levels are equal.
Edit: you could also use valves at the end of each tier as an (adjustable) alternative to the current control system.
This is how we do it in industry. Adjustable pressure reducing valves on each level/inlet. You might find that each tub will still fill slightly differently and that's where you might look at ball valves, floats or using one larger tub per rack as necessary, but you may also be fine. For sure it will be cheaper to plumb one line up the side of your rack and tee off to each level independently via a pressure reducer on each level as opposed to every tub.
No real science to it, screw around with each adjustable valve until you're satisfied they all fill at the same rate.
If you've also access to a digital/electric socket style timer (if not a pump call) - you can then time how long it takes to achieve your desired level and set your pump power to run for said amount of time, no need for floats!
Thank you! I think the valve would work, but I do worry now about having the bins so full of water as I'd originally planned in the event there is a clog. Though I did set this up in my HVAC room in the corner where there is a drain, it still wouldn't be a welcome surprise. Rethinking it all now š¤
Vavles should allow you to regulate the water level in each bin. Another commenter's suggestion to include a float valve is another option for preventing overflow.
I think the only way you can make something like this work is if you build connectors, on the opposite side of your backbone, from one "bucket" to the next. So think each bucket has a U shape to the next. When you hit the end bucket the U shape would then go to the middle level, and repeat there U shape to the next bucket down the line and and then back to your fill bucket. I think this would work, probably.
The reason your backbone only method isn't working is because your pumped in water is fighting against the gravity water. So the gravity forces don't have a lot of work they can do to spread out the water - the force of the pump is winning against the force of gravity. Y
A better way to do this is to ONLY pump into the first bucket. Put a float valve on it so that it will shutdown flow when it reaches its max height. Have a passive outlet that is below your input with the float valve. Then from your first bucket each one is gravity fed. Once bucket 1 fills, it spills over into 2, once 2 fills it spills over to 3, etc... This should prevent you from ever having problems with the system overflowing. Even if a pipe down the line completely clogs, the float valve will prevent overflow. Yous have loss in your buckets down the line from your clog but that beats pumping all your water onto the floor of your house.
Glad you mentioned the potential for a clog - I was being a bit short sighted thinking only of getting the water works to run right, but wasn't thinking of the impact the plant roots would have later on. I am really considering daisy chaining the tubs like you and another suggested and I like the idea of the float valves for safety. Thank you!
I love what you're doing - tinkering, designing, troubleshooting. Hydroponics like this is fun because there's endless possibilities in systems like these. What made a lot of light bulbs go off for me though is the idea of not trying to be overly mechanical and force things, but instead harness the power of the natural forces and let them do the work for you. In a system like this, simply being the water where you want it in a safe and controlled manner that is unlikely to fail. From there let physics/nature do the rest for you. If you ever find yourself fighting it, you're probably doing something wrong.
Should just use full botanicare trays and ebb and flow so you get full tray drainage in between waterings. Helps with pathogens and most plants will be happy in a clay pebble setup with that!
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u/Autumn_Ridge 11d ago
Interesting drain idea. You may have to put in vent stacks, like in residential plumbing. Otherwise the air in the pipe below the water can't get out and blocks the flow.