Baking soda is sodium bicarbonate, bicarbonate of soda, hydrogen sodium
carbonate, or acid sodium carbonate. All terms are for the same chemical.
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RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"billfish" wrote in message
...

The high GH is not due to sea shells as there are none in the pond at
present. I'm not a geologist soI cant say what the exact makeup of the
water catchment is here. I do know however that the majority of the
rock which forms the island is granite and other very hard rocks of
that type. There are no significant chalk deposits. We get incredibly
hard limescale buildup in kettles etc, so the pond GH being high is not
too surprising. Also the lack of limestone or chalk might explain the
low KH value. I will try a test on the tap water as well as a re-test
on the pond. If necessary I will do a part water change and add baking
soda. By the way, is baking soda the same as sodium bicarbonate?

RichToyBox Wrote:

Baking soda will raise the KH without raising the GH hardness. If you
are
getting the high GH values due to the dissolution of sea shells, then
more
frequent water changes would be in order.
--
RichToyBox
http://tinyurl.com/6k2bp

"billfish" wrote in message
...-

RichToyBox Wrote:-
Hard water is really not a problem. -

Sorry. When I typed in my post I didn't realise this forum doesn't
support "more than" arrows. It should have read that the GH is more
than 16, i.e. off the scale on the test strip and classed as very
hard
water. I was a bit concerned because, from what I've read, for most
fish, including GF and Koi, moderate to fairly hard water is
preferable. When you say the KH is at the low end, what should it
ideally be? I live on an island, so seashells to put in the filter
are
not a problem for me if you think it is required to raise the KH.

Bill.--


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billfish-


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billfish