"Hal" wrote in message
...
On Tue, 31 May 2005 23:04:13 -0400, "Paul"
wrote:

Like how much Limestone. One big piece or smaller ones. Thanks...
"Courageous" wrote in message
. ..

Exactly. And the limestone keeps the alkalinity from falling.

In fact, the more that the alkalinity falls (i.e., the water is
becoming acidic), the more likely the limestone will react with
the acids in the water to, um, increase alkalinity.

I've learned different people seem to have a little different
experience and I'd like to share mine. I've been using ground garden
limestone from the garden shop for a number of years. I place about
2 or 3 cups in a sock, tie the top and toss it into the flow of the
water going through the filter. I also add another couple cups
around the pond. The reason for the other couple cups is limestone
doesn't dissolve quickly like baking soda and quite frankly is a bit
frightening after a heavy rain. (Limestone dissolves in less than pH
7.8.) I just don't get the KH readings I feel I should, probably
because the limestone is working so slowly. My normal pH readings
are 7.8 to 8.2 and KH drops after a rain, sometimes as low as one
degree, (1 degree = 17.9 ppm.) but the pH never goes below 7.0 and the
fish don't seem to mind. In fact the seem more active after a rain
nibbling at the liner and collar stones they haven't been able to
reach before.

Regards,

Hal

That is normal. And a 17.0 ppm drop in your alkalinity is nothing to be
worried about as long as it is in the normal range to begin with(~80 ppm).