Although this is an evolution of previously entered work, there has been significant changes to the whole modular idea as well as some control mechanisms added.

I have learned along the way that the back flow of air through the pump IS definitely a problem, especially when working with air tight systems or relatively low height water columns. For this reason, I have added two mechanism to aid with the control of the fill and drain cycles. I have also added a central "manifold" through which all air flows, allowing for expansion/experimentation.

The air escaping through the planters, when the reservoir empties, was also a problem, so I added a separate bottle that I call a bubbler. The bubbler redirects the escaping air and reduces the bubble size, reducing splashing, vibrations and effectively extending the pump on time. I suppose it could be used as a planter as well. Don't know what you'd call the bubble method.

The MODULARITY has been expanded so that the "HUB" of the system is the Bubbler and the TEE below. Everything else is swappable. You can change reservoirs and/or reservoir types as well as "planter lines" and types of planters at your whim. This allows for experimentation and expansion without having to disturb that which does need to be disturbed.

I do plan on improving/screwing with stuff as time goes on and required a "productive" window sill garden that accommodates different designs and methods, without starting from scratch each time. This what I've come up with and hope to be adding "Modules" as time goes on.

Step 1: Modular Reservoir


1 ea 2L pop bottle with cap
Approx. 18 inch length of 3/8 inch OD Vinyl tubing (trim as required in final setup)
1 ea 7/8 inch length of 7/16 inch OD tubing
1 ea 5/8 inch length of 1/2 inch CPVC tubing
Hot melt glue (Silicone would probably be best)


1. Drill one each 5/16 inch and 13/64 inch holes in the cap as shown.
2. Cut both ends of the 2 ft length of tube on an angle as shown.
3. Thread the 2 ft length of tube through the 5/16 inch hole in the cap as shown.
4. On the end of the same tube, that will be outside of the bottle (cap orientation), slip the 7/16 and 1/2 inch pieces over each other as shown to form an adapter.
5. This adapter will leak without tension applied, so hot melt glue as shown to seal.
5.Place cap on bottle and adjust tube so it reaches the bottom of the inside of the bottle.

How much did this cost?
How much would you say this would cost assuming you would use recyclables for the bottles?
Would there be any way of making the system automated? It would be nice to have the pump kick on at preset times through out the day and shut off after X amount of minutes
There is a 6 cycle/day Christmas light timer running the pump. You can see it behind the tea stained reservoir. I keep screwing with the stuff, but generally, it runs 6 times a day for 2 minutes at a time. Things keep growing .... cats keep eating them.
Being ignorant in this field I have to ask what is the purpose of having to move the water from one bottle to another and then back again? Couldn't you just bubble it where it's at? And to what advantage does one get by doing this verses planting in the soil and not useing any energy?
The water moves so that the roots do not drown and stay oxygenated. I've thought about the bubbling thing and I don't see why not. That last one is a question that I'm not going to touch, other than automation. There are a lot of opinions and pros always come with cons.
what is the bubblers purpose? is it a place for the air in the resevoir to go when the water returns? does the bubbler eliminate back flow into the air pump? this is my main concern. ps. very cool, ive been trying to come up with something similar without much luck.
The bubbler's purpose is to give "most" of the air a place to escape through once the nutrient has evacuated the reservoir. The air will continue up the nutrient line and through the planters, otherwise. When the nutrient returns, it escapes through the screw hole and any other leaks in the caps. It should not siphon back because the air line tip is above the reservoir water line and the "screw valve vent" will be the path of least resistance for the escaping air. To eliminate siphoning completely, I would recommend installing a one way (check) valve between the reservoir and the pump as well as mounting the air pump above the water line. It probably isn't actually necessary, and for all I know, the bubbles may be good for the roots, but I put it in to reduce vibrations and noise from large bubbles making it through the system. It took an awful lot of boredom and anticipated future incompetence (not to mention present day incompetence) to motivate me this far, so don't give up...
gotcha, thank you. one think to consider and you mention it--aerating the resevoir water, the oxygen being good for the roots. i think simply running the air pump hose into the resevoir water should do the trick. what do you think?
Yes it would. You would then have the potential of siphoning and would, therefore have to add the other precautions. I did not do this to avoid the siphoning effect AS WELL AS avoid clogging of an air stone. On that note, like you said, just run the hose in w/o an air stone. I also do not believe that it is necessary for two reasons. 1. The roots are oxygenated by the drain cycle's vacuum effect within the grow medium. 2. The gas transfer takes place at the surface, so other than agitation, it would have little effect.
Three questions 1. Do you have any new modules b/c i am interested to build them. 2. Could you post an instructable about a larger system you talked about. I think I would like to line my room with plants :) 3. What kind of nutrients do you use, I am relatively new to hydroponics and could use a few tips.
Some ideas I had that you may want to incorporate.
1. Always working on next module, at least in my head. 2. Just posted what was going to be a larger one, but ended up having to cut it twice, so I stuck with my previous scale. It can easily be made as long as you want and go around corners as long as you keep it level and tap it in various places instead of at the end. A "Sucker Stick" if you will, or individual planters, which could be mounted right on the pipe itself or above it. That's how I've envisioned it. That sucker, made into a single solid unit is then stackable up the wall. Somebody make it stop.......... I'd love to see pics when completed. 3. I just use store bought generic, but "complete" liquid hydroponic food. I am just a beginner too and am trying to work out a system prior to next spring. I have found this site to be the BEST source of info and useful links, by far.
Have to be honest man, you lost me on this one.
It's the same system, with a vent to help the drain cycle (either the DWC or the screw), and I made so that the individual modules (based on function) are easily removable to allow for further experimentation/expansion on/with/to this unit/plants. The vent and bubbler were added to address the problems and questions that people had with the first unit. It automates the drain cycle for those who were manually releasing the air. The rest is just me learning how to "do it the hard way" as I go. I've since removed the DWC from the system and am venting through a screw. It may be re-introduced in the future. It was more of a Eureka moment and an experiment than anything else.... but it does work. I try to exploit every potential I see, to see if it's practical.
Very nice I built a 14 plant system that uses a cheap pond pump almost the same with the 2l bottles but out of 1 inch pvc with a 30 gallon drum for the resivor sorry about the spelling. yours is very cool
Thanks. I'm curious if you had any problems with pump/filter failure. I'm hoping to have several systems set up in the spring for comparison purposes. I'm expanding the reservoir to a 4 footer as we speak, uhhh... type. Dunno how many plants I'll be able to "push". I think the pump should be able to handle "horizontal" expansion with ease, but that's tomorrows module. Off topic.......but......The prototype sprung a leak, at a hot melt glue joint, from moving it yesterday, so I just swapped out the feed tube and "shelf" and plants (top half) in less than 5 minutes, before the pump came on. Worked great w/no leaks or apparent plant stress. Pressure fitting rocks!
Have you tried bigger reservoirs like 10 gallons or bigger?
I mean no, 10 litres or bigger is what I meant. See below. The theory is the same though, at least in my head.
Yes, but in a horizontal reservoir made of 4 inch drain pipe. The horizontal nature of the reservoir allows you to tap it anywhere as well as reduce the vertical forces at odds with each other. I thought about larger bottles, but they would have to be shallow to be effective and could only be tapped, easily, in one location. The horizontal reservoirs could then be shelved vertically without the need of expensive water pumps pushing great heights of water. The "shelving" would have to support the weight of the nutrient anyway....... I could go on and on and on... Sorry you asked, eh? One pump..... MANY plants would be my goal I guess.
This link will explain it better. The original size doc is easily readable.<br/><br/><a rel="nofollow" href="https://www.instructables.com/file/F34GCDZFOD6V254/">Larger reservoir type thingy</a><br/>
It would be so nice to see a video of that working. I just don't get it.
I'll be editing it into the Instructable momentarily. I didn't because of quality, but I managed to get enough detail on the reservoir and DWC unit to be useful. Please try to extrapolate everything that is not in the frame.
Okay. I'm starting to get it. Atleast I believe I am. The dwc is a means to reuse air that would other wise be lost. That is efficient.! 'm not a person who can read plans well and actually need to see the finished product in action to completely understand. I hope you could post a video showing the whole system in action, and for those of us who start out a bit slow, explain what is going on. That would be really useful for pple like me who don't always get something unless you draw us a picture (or vid) Thanks again! I appreciate.
I've added another video of one complete unit, using only the DWC as a vent (and any lack of air tightness), as an edit into the final step. Hope it helps.
I'm kinda suprised that the plant doesn't drown in the DWC since it only gets air durring the cycle. The pump runs how many times a day?
Just set it up, but the plant that's in there is virtually indestructable. It's been sitting in a virtually dry kitty litter container DWC unit for ever, the air stone was not even fully covered and the thing just does not die. These philodendrons are great for testing conditions because they show the signs of stress immediately, but haaaannnnng onnnnn forever and then bounce right back when given favorable conditions. It does look a bit better and there is a rootless piece that broke off in there too. I want to see if the roots will take under these conditions as well. Anyway, I just set it up to go off six times a day for 4 minutes which should drive the flood and drain cycles near perfectly. The plants will be the proof of anything, although I do have a habit of stressing them on purpose.
That is exactly correct. No problem. I'll post something, if I can produce something of useful quality.
I have to say I am quite confused which is a shame because you definitely have something spectacular going on here. First of all I don't see the point of the DWC at all. It looks like a complicated way of letting air escape. And why did you put a hole in the side when you could just have easily put the tubing down the neck that's wide open. And why did you attach tubing to the bottom of the DWC. You mentioned draining and checking the level in there but can't you just look at it and tip it upside down to drain? That tubing at the bottom seems like a leak waiting to happen. And why does the DWC need min and max level markers? If air is just bubbling through it how would the water level ever change? Also, I don't understand if air pressure is rising, pushing up the water in the planters, why would the bubbles be decreasing in the DWC? Wouldn't you get more and more bubbles as the water level in the planters increased? You've clearly put a lot of effort in explaining how you built everything and did a wonderful job I might add. But maybe a little more explanation as to why decided to do some of the things in the first place. I understand the bubbler just not the DWC. I don't mean to be a downer. I actually think this project is brilliant and I don't even know what that DWC is for. After I figure that out I'm sure I'll be blown away.
I will try to answer as clearly as possible, in the order you ask and I don't blame you for being confused because you are correct. The DWC is absolutely unnecessary. The screw valve would have been enough, but that actually came later. In my previous designs posted, people were having problems getting the drain cycle working due to air tightness. I did eventually as well, requiring me to solve my own problem. Having a DWC unit available, I tried it out and it worked. It was only an afterthought to add the manifold and screw valve as a simpler fix. All of my designs will be moving toward accessing everything for maintenance/replacement w/o disturbing the rest. With that in mind, I will explain the DWC unit's design when it could've just been an unmodified bottle. The hole in the side is for filling with a funnel and for access to the air stone, separate from the opening that the plant is in. Once the plant is secured, I use polyester fibre for aquarium pumps, you would not be able to access the nutrient w/o the second hole. I attached the tube at the bottom so that I could drain the waste nutrient, again w/o disturbing anything else. It also would allow me to view the nutrient level once the bottle is covered back up to protect the roots from light. Plants also might not like being tipped upside down once past the seedling stage. You are correct, it is a leak waiting to happen. The DWC unit is a Deep Water Culture is unit meant to grow plants, not just bubble air through it. Once the air starts travelling up the tube, it becomes the path of least resistance to the air. The pressure increases until that point, as do the bubbles. At that point, the larger bubbles travelling up the tube MUST be easier. It surprised me too. I would like someone to explain to me why I do the things I do. Looks like were both out of luck on that one...... You're not being a downer. I expected every question you asked. Although I think I've already answered this, I'll be clear. The DWC is actually a separate planter using a different growing technique. It is unnecessary, but was available to be added to the beast to solve a problem so I MacGyvered it in. I also plan on building more completely useless "modules" to add to it whenever I can. For no reason other than, I can and virtually for free. Someone somewhere said something about air powered aquaponics. Hmmm.....

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