Either limestone, Ca2CO3, or oyster shells can be used. Some say dolomitic
limestone which has a portion of the material as dolomite, CaMgCO3.
Dolomite does not readily dissolve. The geologist tell the difference by
spraying muratic acid on the rock. If it fizzes, its limestone. They do
not dissolve at higher pH values, but if there is enough of either in the
flow from the filter, which should be the most acid, high in CO2, they will
dissolve and prevent a pH crash. They do not give the high KH values that I
have been led to believe are needed for my bead filters, so I use baking
soda.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"~ janj JJsPond.us" wrote in message
...
On 5 Jun 2005 17:22:55 -0700, "mos" wrote:

Yesterday the ph was 8.0 today it is 7.8 and the two remaining fish
seem fine.
She only had tests for ph and Ammonia. No roots or any overhangs,
seems like all the larger fish died, I suppose the dieoff of the algae
didn't help the 02 in the water either. Unbelievable to see that much
algae die off literally overnight....then to loose the fish. She
hadn't checked the pH yet this year, so we had no previous number to
compare. Thanks for everyones help. Maureen

Roy hit the nail on the head, large fish dying first, usually means low
O2.

I would recommend those who live in areas of much rainfall have the test
to
measure KH. Rain water has no buffering, and supplemental treatments need
to be added unless other means are in the ponds.

Okay, help me out RPers, was it limestone or crush oyster shells that was
recommended as a slower method than baking soda to increase buffering?
~ jan


~Power to the Porg, Flow On!~