Hi Muffin,
I agree with Jan. Don't mess with the GH reading. KH is the one you
should actually be worried about - it is the one that measures
Alkalinity...
Do you know whether or not all your test kits are up to date? This was
my problem... mine were last year's issue - hence my panic. They were
terribly
erratic. This 5 tests in 1 is really a great thing to have. It shows
the colors and
inside the label which peels back you have an explanation of each. The
tests it takes are Nitrate; Nitrite; Hardness; Alkalinity; and pH.
(and a "fix" for all the
tests that are off).

Also,when you take the tests, try to take them in the afternoon for a
more accurate reading. Early morning or later in the evening will show
elevated readings.

And finally, I would back off taking any more tests. Just let the pond
and fish rest for awhile ;-)

HTH

Nedra in Missouri
Zone 6