 View Single Post Old 01-22-2013, 07:35 PM   #24 Wy Renegade
Planted Tank Obsessed Wy Renegade's Avatar PTrader: (3/100%)
Join Date: Nov 2011 Location: Wyoming Posts: 370  So the point
has been made that if enough substrate/surface area has been
provided within a tank for bacteria to populate, then the
process of breakdown can occur naturally within the tank itself
rather than in/on a filter.  I would disagree with the notion
that a freshwater tank has a higher oxygen content than a
saltwater tank. Oxygen concentration has very little to do with
dissolved substance concentration in water, it is mainly about
temperature, therefore a fresh or saltwater tank with equal flow
rates and equal temperature should have about the same
concentration of dissolved oxygen. The primary difference is in
the use of anaerobic areas within rock and substrate (often
controlled by substrate depth). Certainly in a freshwater tank
with a fine enough substrate there are anaerobic areas that
support denitrifying bacteria. I personall