I have two refrigerators in my green house, waiting to become insulated water tanks, and I'm driven to stack their functions.
The idea is to grow azolla in a tank and periodically pump some of the plants and water into a vermiculture tank.
The vermiculture medium would filter the water ,leaving the plant to be processed by the red wrigglers.
The water, filtered of solids but rich in nutrients, would circulate through a flood and drain tray and back to the azolla tank.
That's the basic idea.
I realize that even azolla might not grow fast enough to sustain harvest if harvest is tied directly to the flood and drain cycle, so two separate pumps might be best.
For reasons of space and conserving heat, I am wondering if the azolla could thrive in a completely closed tank, with an air bubbler, under artificial lighting.
They are said to prefer partial shade, so low light might be fine.
The light itself will contribute to heating the closed tank, which, up to a certain temperature, would be beneficial.
This will probably be the first thing I try(if anything) because it will be fun and very informative.