Modular, Windowsill, Air Powered, Hydroponics Herb Garden/Experimenter

Step 8 Operation and Operating Parameters

Turn on and inspect for and repair any leaks, both air or liquid.

FILL CYCLE

Pump comes on and pressurizes the manifold, initiating the emptying of the reservoir up the tube and into the Flood and Drain unit, as well as the bubbling of the air stone in the DWC unit. This continues until the reservoir completely empties or equilibrium is reached between the opposing forces. It can be "tuned", and will be discussed seperately. As the reservoir empties, the bubbles will be redirected, largely, up the tube and into the bubbler rather than the air stone.

The greater the resistance from the air stone, the faster and more completely the reservoir will empty.

DRAIN CYCLE

Pump goes off and the water that has evacuated the reservoir returns under the force of gravity. The returning nutrient pushes the air up and out, into the manifold, and out through the DWC air stone as well as any other leak available. The bubbling of the air stone will reduce as the weight of the returning nutrient diminishes, until all of the nutrient returns or an equilibrium of the opposing forces is reached. This can be easily tuned as well.

Please see video for demo of unit w/DWC only as a vent -

Please see video for demo of reservoirs only-

TUNING

Tuning is achieved by varying the opposing forces, such as gravity and air pressure. Generally speaking, gravity affects various "thresholds", while air pressure affects rates and the ability to reach the thresholds or a state of equilibrium. At least in my understanding and my ability to explain same. Lets just say, it's a balancing act.

The effects of gravity can easily be varied, and observed, by increasing or decreasing the height of the planters w.r.t. the reservoir or by varying the depth of the air stone in the DWC unit.

The effects of air pressure, acting against gravity, can be regulated by the porosity of the air stone in the DWC unit, by varying the depth of the "self tapping screw valve" in the manifold or reservoir lid, or any other method of controlling the "air tightness" between the air pump and the reservoir.

Using air tightness only, one can overcome the issues with the slow drain rates regardless of pump used, as long as it can supply enough air and pressure that is. With the DWC unit eliminated, the excess air will simply vent out the screw valve thingy.

NOTE: Only one complete system can go onto any one individual pump because of the pressure loss that will occur when/if the reservoir empties. Any slower systems will stop filling, and start draining, when the first one starts bubbling. One larger, shallow reservoir would be preferred over multiple reservoirs in larger systems.

Comments

[Groove22]

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

[wiley coyote]

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.

[runningman53]

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?

[wiley coyote]

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.

[awakebyjava]

Have to be honest man, you lost me on this one.

[wiley coyote]

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.

[tabletopphoto]

It would be so nice to see a video of that working. I just don't get it.

[wiley coyote]

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.

[tabletopphoto]

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.

[wiley coyote]

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.

[tabletopphoto]

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?

[wiley coyote]

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.

[wiley coyote]

That is exactly correct. No problem. I'll post something, if I can produce something of useful quality.