Aquaponics - Absurdly low energy system

I've had an idea.

It's been a while.

I keep running the problem of a low energy system through what I like to call the invention engine, and it keeps telling me to lower the difference in height between the fish tank and the grow bed. Eventually it told me to make them at the same level, and use a powerhead to just stir water from the fish tank to the grow bed.

But when I run it with the new system design, it says to drop the grow bed even lower.

Into the negative.

Which doesn't make a lot of sense until you think about moving the grow bed back up again to drain it.

When I ran that through the invention engine, it came up with floating the grow bed in and out of the fish tank.

By pumping air under it.

An air pump is inexpensive to run, and I know it's already capable of the pressure required to get air to the bottom of a tank, because a lot of people use them in exactly that way.

The thing I dont know, is if it's capable of shifting enough volume to raise the bed often enough. It will definitely raise the bed, but if it takes too long, then it's not going to be worth it. I'm guessing I'd need to raise and lower the bed at least twice per hour. Dropping it back down should be easy to make quick, so as a target to aim for, I think I'll look at raising the grow bed within half an hour. 

So if I put a grow bed on another, inverted growbed, I can fill the bottom (upside down) one slowly with a small air pump, and effectively, float the grow bed up and down rather than shift the water up and down.

As the grow bed lowers into the water, it displaces water, causing the fish tank water level to rise, and thus contribute to submerging the media to the desired level. The reverse would occur when the air was trapped and the grow bed rises. It would displace less water, so the fish tank level would drop, resulting in a quicker low tide.

The air pump can be even smaller than I first thought, because there's really no need for all that pumping to the bottom of the tank, so no need for all that pressure. That combined with the way all that stuff in the previous paragraph should work, might mean it will be an absurdly low energy use aquaponics system.

I haven't worked out the down bit, but that wont prove difficult at all. I really enjoy inventing things where the force I'm trying to overcome is used to do the overcoming, so in this case I'd like to make use of the pressure build up to release itself, but even if I cant work something out, I can always use electronics to make a valve open at the top of the cycle, dumping the air, and dropping the grow bed back down.

I might even be able to use the rush of air to do something productive.

Cooling perhaps... who knows.

It might even be possible to use the incoming water from an existing system to get a free lift, by using it to force some bubbles under a new air powered grow bed.

Or to fill the grow bed, raise it, and then distribute the water to another grow bed, creating a kind of pump.

It might also need a few guides to keep it from wearing where the grow bed would inevitably touch the fish tank.

I have a really spooky feeling I've had this idea before, and this may just be a side effect of my current lifestyle (that being sleeping in a post-op haze) or could just be because I have had the idea before. Or it could even be confirmation of the sneaking suspicion, that whenever I have an idea, what I'm really doing is simply remembering having had the idea in the future, at some point after that.

This means all the invention engine does is jogs the memory I'm yet to have had...


Either way it will work.

All it would need is a grow bed media that weighs less than the water the air displaces, and it will work.

And some buckets...

I'll need some buckets.

I'll make one tomorrow.

Buckets, and media...

I'll need some media.

Sleep now.

120 Things in 20 years, For all your absurdly low energy aquaponics systems and pre-think.


  1. Two grow beds...

    Air lift one, the other sinks. Air from the sinking one flows over to the lifting one, speeding the process.

    The seesaw could also help keep the grow beds off the tank walls.

  2. TCLynx also mentioned a Teetertotter (sp?).

    I'm not sure you could reuse the air though because it would have to be under pressure to go in, and have to release pressure to go out. I think you might get some kind of equilibrium between the two beds. But I guess at that point you could switch to exhausting the air.


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