I just added a bead filter to my smaller pond this year. I have not found
that it needs any more baking soda than it used to require. I am very
diligent about measuring and maintaining a minimum of 100 ppm, but generally
don't measure how much I use. A 12 pound bag from the discount club is
cheap, and I dump in about 8 pounds into the larger pond and about 4 pounds
into the smaller pond and wait for the KH to fall, which could be 3 or 4
weeks. A veggie filter of the anacharis and other submerged plants will
actually increase the KH without addition of baking soda and help to
stabilize the pH significantly, but my koi love those types of veggies and
without a separate pond that form of filter would last only minutes.

--
RichToyBox
http://www.geocities.com/richtoybox/index.html
"~ jan JJsPond.us" wrote in message
...
Case in point, one of our ponders started out with pressurized, and was
about ready to take out stock in Baking Soda the way he went thru it. He
has since converted to a gravity fed filter, and says it's a rare day that
he needs BSoda... and his fish have gotten bigger in the meantime. So
there
has to be something directly to do with that type of filter, not the pond,
per se, imo. ~ jan

On Tue, 17 Aug 2004 00:32:28 GMT, "RichToyBox"
wrote:

The KH is consumed to an extent with all filters. The bacteria use the
carbonates to help with the digestion/conversion of ammonia to nitrite,
giving off a Hydrogen ion, and then in the conversion of nitrite to
nitrate,
2 Hydrogen ions are given off. These hydrogen ions are acid and they use
the carbonates to neutralize the acid and convert the hydrogen ions with
CO3
to CO2 and water. The pressurized filters, bead filters are generally
associated with heavier fish loads than the garden pond with smaller
filters, and therefore more food to be converted, more acid, more demand
for
carbonates/bicarbonates to prevent a pH crash.

~Power to the Porg, Flow On!~