Aquaponics

[Mightysword]

Nice. I may have to resort to something like that, i would prefer it if the mass movement from the plants could generate a similar effect.

It's not the movement but the surface tension that promote air exchange. Most plants actually don't like to have their root disturbed too much, so having a current strong enough to promote sufficient air exchange may be bad to them. Speaking of experience, I once have a set up with a slow too strong and it make the roots all tangles up and it kinda stunt the growth of the plants. Also it might not generate enough oxygen if you start getting green water which you will most certainly do with the high amount of nitrogen waste and direct sunlight.

Do not overestimate the need of nitrogen of plants, they require a very small amount very slowly, almost guarantee slower than what your fishes will produce. That's why in aquarium, it takes a large amount of plants that turn the tank practically into a rain forest to achieve a perfect balance just for a few fishes.

[philip_hughes]

Totally agree. I plan to break the surface tension by using a flush system. Once the water level drops below xcm, a valve opens and water rushes through. I need to get things moving first, so your solar airstone may have to be there, just for the first few weeks.

From the worm experience I know there is a definite O2 limit in the tank.

[Mightysword]

Totally agree. I plan to break the surface tension by using a flush system. Once the water level drops below xcm, a valve opens and water rushes through.

In that case you may try something like a Gravity Feed Sieve with floating valve? It'll come with the benefit of removing algae from the water column if you can find a fine enough mesh.

Here is a thread that includes pictures and dimension for a DYI one, you can make your own blueprint and scale its to your application, I think it's possible to modify the design with a check valve for a flush/no pump system.

http://www.koiphen.com/forums/showthrea ... eve-filter

It'll take some work but once you have a blueprint, you can use a good 3D printers to create most of the part, since you're a university professor I think there are a few around most campus. If your department doesn't have it, check with the people who do Trading Skill deparment assuming your university has such program (CAD designers, Welding, Machinist, Manufacturing program ...etc...).

[philip_hughes]

Not quite a professor, but thank you. Actually, now you have said it, it must be true!

**rushes out to make business cards

[philip_hughes]

The seedlings have established taproots that can reach the water table. Mass movement has begun!

[philip_hughes]

So guys. Bearing in mind it is still very early in the process, so lots can still go wrong. ...

I am reasonably confident that you can use capillary action to create a static hydroponic system.

Pros:
-cheap
-few/no inputs

Cons:
-requires a lot of fish keeping skill
-if/when it goes wrong it is catastrophic.

My lettuces are growing. They are still small, but they are losing their embryonic leaves and you can see recognizable lettuce leaves. This means the seed are no longer relying on their reserves and are taking nutrients from their environment. I need to figure out if these plants can exist in a semi-saturated medium. It has trained so the water levels are high.

Everything is going well!

[philip_hughes]

Lost some fish last night when the outside temperature dipped to zero. I will have to time the injection of laundry water- it can be quite warm. I'll put it in just before i go to bed.

[philip_hughes]

Lost another three fish last night. Transferred the rest to an indoor tank. It was obviously to cold for them to survive. My hands hurt as i was putting them into the water to catch the fish. Rather than swimming away, the fish snuggled up to my warm arm. They are now cozy if overcrowded.