Why not just make a very low light (or a no light at all) moss only tank? Here's a good example:
Front:
Top:
- Manzanita.com branches wrapped in moss
- any gravel (not nutritious) will be fine
- less than 0.5 wpg of any light you want
- a small air driven sponge filter for some economical water movement
- any dwarf shrimp you want
- malaysan trumpet snails
- few small livebearers
Done.
That is not a plan for a self supporting system. There is no "A feeds B -- B's waste feeds C -- C feeds A". That's a plan for a 99% hands free tank. You will never have to wipe off algae. Evaporation will be the only thing that will invite water changes.
--Nikolay