Note: freshwater aquarium dynamics have much in common with two areas for which a wealth of scientific literature exists: (1) water chemistry in lakes and ponds, (2) the chemostat problem (as discussed in class). You may want to search through some of the literature in these areas.
The Nitrogen Cycle
A nice description of the nitrogen cycle, and key factors involved
in the process.
Do your own searches on google, there is plenty of information on the net.
On Reserve at Marriott Library:
"Seawater Aquariums, the captive environment" by
Stephen Spotte. SF457.1 .S67
About saltwater, but has lots of good information.
"Dynamic Aquaria", W.H. Adey and K. Loveland. SF457.5 .A33 1998
See in particular Chapter 11.
"Introduction to Natural Water Chemistry" by
Gordon K. Pagenkopf. GB855 .P33
Background information on water chemistry.