Backyard Aquaponics
A place to discuss aquaponics

My brain keeps telling me there should be a way to do a really simple single tub ( both growbed and fishtank ). Here's a quick sketchup of what I've been thinking. I've removed the front wall so the inside can be seen.

The idea is that there is a sump inside the tub itself, whichs fills and empties itself somehow thus changing the height of the water in the tub and therefore flooding and draining the media. The media could be in pots sitting on the sump.

The two ways I can see working for the sump, is a pump on a timer to pump the water out ( what happens when it gets dry though ? ) The second idea was a strong air pump pumping air to the top of the inside of the sump, it should build up air-pressure and push the water out of it through a hole near the bottom, after a set amount of time the air pump would turn off and the water force the air back through the airpump backwards ( assuming this is possible? )

Thoughts?

Interesting thought UT.... Perhaps a small hole in the top of the sump box and a reasinable air pump pumping into the sump box.. Inflow of air is greater than the whole out so it pushes the water out raising the water level, flooding the plants... Then air pump turns off, air continues to escape via the bleed hole in the top..

Only thing is that it's a bit of a waste of space having that big bog inside the fish tank, need to find a way to make use of that space for fish as well or something...

Yeah I thought the same, but if it empties out, then not much you can do.... Maybe you could put crayfish or some other species that can survive on little to no water for short periods of time?

What I'm trying to think up is any easy first aqua kit for a new starter to get the hang of things before moving to a full on system. Could be something that you could sell with everything included as a startup.

Doesn't really need to be efficient, if the reason behind it is learning how AP works.

There are a few small systems on the forum that are reasonably efficient UT, try looking here
Small systems

Solids removal could be an issue unless you don't expect to feed much.

Edit: Contemplative Update:

I might suggest a fairly steep, conically shaped bottom for the fish tank with a valve at the bottom to draw off solids after they build up.
Instead of a box, you could have a bladder/balloon that is anchored to the bottom. This bladder could now displace the water to flood the grow bed in a tidal type manner, passing it through the filter.
It would also collapse to reduce the space it takes up for the fish.

....Could be an interesting spectacle for the fish

I know, I know, your intention is to be simple.
....I can't help it.

That's not as silly as it sounds!! You could have an air pump fill, and then empty the bladder inside the tank, displacing the water and creating the tides.

A small sponge filter could take care of the solids, and keep the water aerated.

I guess it depends on whether you are trying to grow fish for food, or as ornamental. Unless removed, the solids would suffocate the fish if they are fed to have them grow reasonably.

The issue as far as I know would be this:
One would need to have a pump capable of building pressure. These pumps are more costly as they require engineered seals, unless you went with an air compressor with a tank. You would need an electronic(solenoid perhaps) valve to actuate the air stream, but this would give you sufficient pressure.
Most of the cheaper high pressure pumps cannot stand operating under that kind of stress I would believe...at least efficiently.

Yeah that's true... So how else can we achieve a single tank AP ?

What about a a tank with a ledge to put some baskets in, each basket can have a verticle air stone up the middle and filled with media. This would force air through the flooded media, providing the needed oxygen for the roots. The pots would sit so the top inch or so of media is outside of the water.

Would this be enough to ward off root-rot? Probably be okay for lettuce etc, which might be all a beginner would grow...

Forcing air through the media, would create a flow of water to work as filtration ( like the air-pump based aquarium filters ) and if needed a small sponge based filter could be used to collect the solids.

I think you might have some success with a plant at the top of an airlift tube. Have the roots grow down the tube. It may need to be a couple inches wide at least.
No media would be needed. Effectively DWC(Deep water culture), but with direct aeration. You would have to make the airlifts have prefilters so solids do not contact the roots as much. Have a sponge filter for your bio, and some plants will grow.
Or stock your tank with non herbivorous fish and you could float some plants on rafts.
With sufficient aeration many plants will grow submerged.

OK, you have got me thinking laterally.
Why not have the pond on a pivot and rock the pond so that the grow beds on the edges are flooded when the pond rocks past the mid point. You could have a bed at each end of the pond which could be flooded and drain when the pond rocks back and forth.

How to initiate the rocking?
As it needs to be a very slow process (about on cycle per hour I suspect, then the water flowing into the grow beds would tend to shift the centre of gravity well past the fulcrum, so significant energy will be needed to cause it to rock back to the centre from either flood position.

Use that air compressor and some solenoid valves to switch air to a couple of balloons under the grow bed areas, to lift them back to the centre position. A timer could be used to switch the air valves automatically.

I think that it could work, but would also need a latch of some sort in the centre position, so that it did not just rock from one side to the other and back, not allowing the beds time to drain properly and stay "dry" for 20 - 30 minutes before re-flooding.

Just my 5c worth.

Tony

If the fulcrum was around the water level it would be quite balanced. Much less energy would be needed to rock the tank, as the water would not effectively be moving... Similarly weighted, suspended growbeds would need to be angled slightly for even flooding. In this scenario the main issue is a pivot that is very solid with quality bearings to hold the water.
Good thinking!

You could hook up a whoopie cushion to the see saw balloons to add to the fun!

What about floating rafts on top, with some way of filling floats with air then emptying them so that the raft goes up and down? Would that ram air pump thing that was discussed a few months back work for breaking this much wind?

Dave, you stole my thunder! I was also thinking about the idea of floating rafts with mesh baskets to hold the plants. Of course he could also go with trays or common plastic window boxes with the drain holes open, suspended in the tank so that the bottoms of the containers are in contact with the water, then run either a line from a submersible pump up to the tops of the containers to provide constant/timed flooding or an air line from a pump split so that it provides oxygen back into the water, plus operating a siphon action pump (like the ones for cleaning the gravel in the bottom of aquariums) to cycle the water.

(Sorry, I wrote a run on paragraph! )
Kevin