Even Simpler Flood and Drain System - the Mosquito





Introduction: Even Simpler Flood and Drain System - the Mosquito

Due to the response of the last hydroponics system Flood and Drain from Junk, I figured I'd get this down while it's hot in my head because it answers some of the questions. Please do refer to the link above as it explains much of the theory.

I've simplified the system further to lend itself to massive expansion. The planter bottle has been modified to eliminate the need for interconnecting hoses as well as make it accept ANY airtight, and I recommend RIGID, reservoir. It sort of reminds me of a mosquito and works much the same way. As the air pump increases the pressure inside the reservoir, the nutrient sol'n is forced into the body of the mosquito. When the air pump is off, the resulting lower pressure allows gravity to return the nutrient to the reservoir and empty the body of the mosquito.

Modify as required and desired. For simplicity, I've quickly built a two planter unit out of stuff I had on hand and have ignored any efficiency issues. This is more to show the concept and although it "works", this one will not be used as a unit itself. I have also not filled the planters with bags of grow medium and plants for this same reason.

It'll be real short, I promise.

Step 1: What You Need

One airtight reservoir
One air pump
1/4 inch air tubing as required
Two pop bottles
Two 12 inch pieces of 1/2 inch CPVC pipe with one end cut at an angle
1 ea 5/8 inch drill bit
1 ea 7/32 inch drill bit
1 ea 9/16 inch drill bit (please pretend that's what's in the picture)
One drill (not shown)

Step 2: The Mosquito

Drill 5/8 inch hole in lid of any plastic beverage bottle. I used 500 ml pop bottles for this one.
Cut the bottom off the bottle.
Place bottle upside down on pipe.

It kinda resembles a mosquito, don't ya think?

Step 3: Reservoir

In the lid, drill one 7/32 inch hole, through which, we will feed the tip of the air hose.
Also in the lid, drill two 9/16 inch holes through which we will gently force the pipes. Works best on warm plastic.

Any reservoir will work as long as the pipe can reach the bottom. The more rigid, the better.

Sorry, forgot to take picture.

Step 4: Assembly

Gently drive the angled end of the pipe through the undersized 9/16 inch holes like a hypodermic.
Insert tip of air hose through the undersized 7/32 hole.
Fill with water and turn on.
Seal any leaks as req'd.
Adjust min/max and timing as req'd or desired.

It was at this point that I realized that the more rigid the reservoir is, the better. I'm thinking 4" drainage pipe.

Fill planters with a grow medium. I would use a small chip bag with holes as a removable, grow bag "sleeve", but you can use any medium as long as it cannot flow through the pipe and into the reservoir.

No boring video. Trust me, it works.



    • Pocket-Sized Contest

      Pocket-Sized Contest
    • Paper Contest 2018

      Paper Contest 2018
    • Science of Cooking

      Science of Cooking

    We have a be nice policy.
    Please be positive and constructive.




    Can you explain how you made the second rigid tank? It looks like drainpipe. Really good instructible, thanks. I hadn't grasped why anyone would go for airpumping rather than water pump before reading this, but of course it means you can feed many chambers off one pipe/ pump.

    It is drain pipe, that has been capped with heat shrunk 2 liter pop bottles.

    The reservoir, itself is here.... https://www.instructables.com/id/Modular-Hydroponics-Low-Profile-Reservoir/

    Interesting, but I would still use a water pump. Of course a water pump can fail, but the airtight seal (which the system relies on) would be much, much more prone to failure than even the cheapest aquarium water pump.

    The systems actually do not drain if the seal is too airtight, and require some leaks, either by chance or intentional, in order to work properly.  If the leak is too big, it will fill too slowly, if at all.  If the leak is too small, it won't drain.  It's a fine tuning thing.

    I don't, however, recommend building this unit as shown.  It was more of an experiment.

    I'd also like to add that a version of the "experimenter" has been running failure free for over a year now.

    interesting, interesting... What about if it goes too far and starts spilling, I don't want to babysit it for 5 minutes... If I was going to babysit it, couldn't I go even greener and use a footpump for an air matress?

    get one of those giant soda bottles

    Good point, but no. Hmmmm...you could use an air bladder (aka strong plastic bag) somehow as a limit switch inside the reservoir. Preset displacement. Greaaaat......here we go again. Anyway, you would put only enough nutrient in the reservoir to fill the planter to a max level, at which point bubbling would start. The bubbling will quickly prompt you to turn it off, buy a timer or setup a limit switch type gizmo thingy. I opted for a Christmas light timer. I may have to invest in a foot pump over the Holidays. Fine tuning of the fill rate can be achieved either through varying the airflow into the reservoir via a control valve on the air line or by making holes in the system above the water line, which would be highly unrecommended, but effective.

    how bout one of those blowoff valves, like on a portable air tank? do they make them in that low of a pressure?

    I've tuned it using an adjustable air valve using a small self tapping screw. If you introduce an adjustable leak, you can tune it to a certain level, but I'm not sure how time would effect the process, with nutrient level changes and clogging of the hole over time. To actually answer your question though, I'm sure you can find all kinds of miniaturized components for everything these days if you know where to look. I do not.