Operation free food is dead in the water, so to speak.
A few notes on this.
This system was based on the absolutely most basic design that I have seen work as an OUTDOOR design. Reduced and brought indoors it was essentially designed to fail.
What the plants were clearly getting enough of was water and nutrients. What they were obviously lacking was oxygen and light.
Light is obvious. Outside you have sun, inside you have none.
Oxygen isn't as simple. Plants absorb oxygen through their roots. Grown traditionally this is easy, with aquaponics it becomes more difficult. With roots that are permanently submerged the plant begins to drown so you need a way to get oxygen to the plants.
There are 2 main ways of doing this.
The most common is what's known as an ebb and flow or flood and drain system where you set up a valve that periodically drains all the water from the growbed forcing the roots to draw in oxygen.
With a wicking bed like mine where the bed is always flooded you need to enrich the water itself with the oxygen that the plants need. Naturally this is done when rain, wind or particles disrupt the surface causing bubbles to increase the surface area on which oxygen can bond and be released into the water, this still might not be enough though. To have a permanently flooded system you would need to incorporate an air pump, this can be used in 3 ways.
1. You pump air directly into your reservoir, increasing the level of oxygen in the water that is then taken to your growbed by your submerged pump.
2. You connect your air pump to "air curtains" which run in the growbed themselves to directly feed the plants with oxygen.
3. This is slightly more complex but can also be more efficient. Using a dual output air pump you have the 1st output connected to an air curtain in the reservoir. The second output you have a length of tubing which runs through the reservoir up to your growbed. In the section which runs through your reservoir you have a hole which sucks in water as the air flows through. This will allow your air pump to pump your, now oxygen rich, water from your reservoir to your growbed.
The size of your grow medium is also important. Where a smaller particle increases the area for bacteria and nutrients it also suffocates the roots. Your medium should be around an inch in diameter.
I have mocked up a few designs for a new multi-tiered system with fittings for grow lights and an air pump and future expansion to run in on solar.
The positives from the experiment so far is that I have determined that it is possible to, quite quickly, establish a system which produces a substantial amount of nutrients with very little input and with only a small number of small fish.
