On Thu, 5 Apr 2007 15:53:55 CST, Altum
wrote:
GH = the total amount of both calcium and magnesium, so if your GH is
acceptable and you're using natural limestone or oyster shells you have
enough of both. You can increase only the KH very easily by adding some
baking soda. Use 1 tbsp per 100 gallons to raise KH by about 2 degrees.
I seem to recall reading that calcium in the water was measured as GH
and the calcium carbonate was what raised the KH. Led me to believe
the calcium carbonate and bicarbonate worked, but calcium was
different for some reason???
I've used baking soda, but it is so temporary and that is risky for
me. It interferes with the dissolving of the calcium carbonate by
raising the pH with bicarbonates and becomes an endless cycle of
adding baking soda weekly.
Your low KH reading is a little unusual. If you raise the pH of typical
tap water to 7.8-8.2 with calcium carbonate, it goes well above KH 2-3.
Do you have cement, cement blocks or any form of lime in the pond
that's pulling the pH up?
No cement, or anything with lime, except a sock of ground limestone in
the water flow. I use garden soil for lilies and plastic pots, with
plastic half barrels for the fish to hide under and filter materials
(mostly plastic, some wood frames) and a pump. Three different liner
types, molded plastic, rubber and Permalon. PVC pipes and one acrylic
tube that runs above the waterline from the molded pond to the
Permalon lined pond.
I've read fish farmers (Catfish, bass and bream) in this area are
advised to lime the bottom of ponds if their KH is not up to 20 ppm,
but for koi, the AKCA, article by Norm Meck, recommends a minimum of
50 ppm on KH.
I don't usually meet that recommendation, but would like to.
Cut follows:
In an established pond, the ideal
Alkalinity measurement should be around 100 ppm. Readings from 50 to
200 are acceptable.
Cut from:
http://www.akca.org/kht/H2oQual.pdf
Someone at a Koi Society meeting advised adding the calcium used in
swimming pools, but I couldn't find out which lime they were using in
the calcium preparations for pool maintenance, so I haven't tried
that. Soda ash was used to bring up the pH in pools where I worked
some years ago, but I seem to recall there was a reason not to use
that in koi ponds.
Regards,
Hal