Peat Moss - how does it work?

> I just dumped a whole lot (approx. 1/4 of a 350 cubic inches bag) of
> peat into a large bucket of hot tap water this morning.  The tap water
> has pH 8.2 and approx. 20 dGh & dKH (350 ppm CaCO3).  This evening the
> water in the bucket (nicely tea-colored) had a pH of 6.6, GH < 1, KH = 8.
> What happened to the hardness?  

Organic compounds in the peat moss are chelating or binding positive
ions like calcium (Ca++) and magnesium (Mg++) and removing them from
solution, reducing the GH.