re:Balance and lighting

I haven't been following this discussion for very long, so please
forgive me if I'm repeating what has already been said. I would
define balance as a steady state: everything that goes into the
system should come out in exactly the same proportion. It should
be easy, just use your handy mass spectrometer to measure makeup
of the food you put in and the plant material you remove. Seriously 
though, I've often wished I could see what elements make up the 
latest variety of algae taking over my tank. It would be great if
there was a reference somewhere with this kind of information. You
could tell what elements you had a surplus of by identifying the
type of algae. If there was a similar reference for plants, you
could figure out what new plant to use to correct things. 

Glen Osterhout