Covers a lot. Very useful. Starts a bit like some school geography lessons about the water cylce....clouds...rain...evaporation etc, but quickly gets into the details of the Nitrogen cylce and everything you need to know with recommended levels of stuff in the water and how to test for it. Loads of pictures and tips. Well worth the cash! (The worst thing about the book is the layout, it opens up like a flip chart style, but this allows for better pictures....)
Gives sample fish for different water setups, ie. acidic, basic, brakish. Does not look at Marine setups.