peat and soft water

[Frauley/Elson <fraulels@minet.ca>]

Hi all,
I've been following the various threads about peat, and tried an
experiment as a result. I took two 27 gallon tanks I wasn't using
anymore, and put about 15cm of peat moss in each. I then filled them
with Montreal tapwater (pH 7.4, 140 ppm, buffered to the point that even
in careful experiments with absurd amounts of acid, it always bounces
back to pH7.4).
The result? In 24 hours, I had a pH of 5.8 and a measurement of 10 ppm.
I know from keeping delicate killies that the garden centre peat I'm
using is clean of insectides, fertilizers, etc. 
It seems too easy. Any comments?
- -Gary