Wow, these responses have helped me dramatically. Thank you. I have learned so much from the links people gave me. I never had heard the word aquaponics until yesterday. Now I have learned there is a magazine devoted to it. Issue number one is online for free:http://www.byapmagazine.com/BYAP_Magazine_Issue1.pdf
It seems like the perfect system for use on a bus, as the water is reused over and over again. No need for dirt either, as there is special man made 'gravel' that is like puffed up popcorn clay with lots of air bubbles in it to increase the surface area for beneficial bacteria to reside. I haven't found the spec as to how heavy it is, but the super high productivity of an aquaponics system suggests I might only need to cover a minority of the roof, not most as I had been thinking about.
The thought of growing fish in a storage bay seems crazy, but it looks practical from the little I know about it so far. Does anyone know if fish need much light or any light? These aquaponic systems use a high density of fish, say 1 pound of fish to 1 gallon of water, to make the required nutrients for the plants. I am thinking about installing a small prototype system just to see how practical this all is, and then just run it for an extended period right at my home in San Francisco, where I also store my RTS. The weather is so mild here that I won't cook the fish in a hot storage bay, especially if I insulate the tank.
These systems use a sump pump to periodically flood the plant growing container with fish water. Then that water is allowed to slowly drain back into the fish tank by gravity. This gives the plant roots an ideal balance of being flooded and not being flooded, according to what I've been reading. I have a spare 24 volt macerator pump and a float switch, so I can make a 24 volt sump pump from those items I think.
I am thinking of using a 40 gallon white fresh water tank for the fish tank, and the same kind of tank to make two growing containers, cutting it in half lengthwise. How might I make a clear plexiglass viewing windows in the fish tank so I can see what's happening in there? Are there marine products I could buy and install in the side of the tank? I was thinking about installing the fish tank on a Joey bed type slide so I can pull it out from a bay so I can get good access to it. Ideally, I would like to be able to put a top mounted 'door' on the fish tank that is liquid tight when closed, but big enough I can stick both my arms in there for cleaning the inside walls, and so I can easily get the grown fish out for eating.
This all seems so crazy to me, but people are doing this aquaponics stuff all over the world, and its fans seem to be really into it. If I do this, I can go fishing in the bus, instead of taking the bus to go fishing... lol
This is a making me think I'll put the chicken idea on the backburner, and just try to get a small demo aquaponics system set up, maybe in my backyard first, and then on the bus.
Has anyone here done land based aquaponics?
Thanks again to all the great replies. This board is just a fantastic, life changing resource.