Barrel-ponics by Travis W. Hughey
"If you are looking for an introduction to aquaponics that is simple to build, fun
to watch and demonstrate to friends and family the joy of soil less gardening.
This small unit may be for you. It is capable of growing various vegetables and
herbs and would be a wonderful addition to the home kitchen as a source of
fresh herbs and occasionally (depending on the species used) a fish or two.
What it most likely won't do is provide the vegetables to sustain someone on it's
own. That is for a much larger system. Fish production is also limited because of
the small size of the unit. The actual production possible is mainly dependant on
the operators ability to manage it. I have personally grown tilapia in this system
to about 1/2 Lb. Not a lot of them, just a few. I have grown tomato plants and
papaya trees in this system with nothing more than 4 each of 1/2Lb. tilapia as
the nutrient source. Remember this is not magic. This systems fish tank at the
lowest point in the cycle will only have a little over 20gal. of water in it. In my
opinion it's simply not practical in the real world to grow high densities of fish and
have a system that is forgiving at the same time. This unit is specifically
designed as an introduction to aquaponics and to make one familiar with the
principals involved with minimal expense. It is very adaptable to situations where
conventional electric pumps may not be practical. This is all about learning fun
and not intended to be a commercial unit in itself although I believe the principles
can be enlarged to do so. Please read this material in it's completion before
attempting to build this unit. If you are unfamiliar with something don't worry
about it too much. It will come clear as the project progresses."
http://www.aces.edu/dept/fisheries/education/documents/barrel-ponics.pdf