that sludge is anaerobic, and anaerobic digestion releases hydrogen
sulfide H2S, which when combined with water is sulfuric acid H2SO4 ...
an acid. Nitrogen is released, bubbles rise to the surface and leave
the pond.

I would like somebody to do an experiment!!!! Ingrid

On Tue, 3 Jul 2007 14:57:25 CST, "George"
wrote:
The sludge I was referring to occurs on the bottom of
the pond where detritus settles out and can become anoxic in areas with
little or no water flow, especially where there are rocks piled up.
the pH, over time will begin to rise because of the
build up of sludge on the bottom. That's my understanding of what happens.