CaCl to raise GH not KH?

>From: ac554 at freenet_carleton.ca (David Whittaker)
>Date: Wed, 15 Jan 1997 06:13:23 -0500 (EST)
>Subject: Re: Aquatic Plants Digest V2 #447
>Craig Bingman mentions....
>>Chloride ions are 
>>essentially unreactive.  It is the major anion in seawater, but usually 
>>it isn't the dominant anion in freshwater, or it is about as abundant as 
>>sulfate or bicarbonate.
>>Some fish from very soft water may be somewhat susceptible to high Cl-.  
>>Generally, though, at low concentrations, it is completely innocuous.  I 
>>doubt that there will be enough Cl- buildup from the use of the 
>>fertilizer that you mention to cause problematically high Cl- 
>>concentrations if you perform even occasional water changes.
>There are four pie charts on page 68 of the Optimum Aquarium where
>the authors analyze the cation and anion concentrations in both
>mains water and waters from Cryptocoryne areas that they had sampled.
>In the Cryptocoryne areas the average in % mval for the chloride
>anion is given as 51%; in mains water 20%. FWIW
>- --
>Dave Whittaker
>ac554 at FreeNet_Carleton.ca

Since waters from Cryptocoryne areas contains a large percentage (51%)
of chloride anions, wouldn't Calcium Chloride (salt used for de-icing
roads and sidewalks) be a good way of raising GH but not KH?

What I was thinking of doing was to use Calcium Chloride to "tweak"
the GH/KH from say 2 degrees GK and 4 degrees KH to somewhere closer to
about 4 degrees each GH and KH.

Since I use Sodium BiCarbonate (baking soda) to raise KH, I'm guessing
that I may have be careful not to get too much table salt (Na+ and Cl- 
cations/anions) in the water, but I would think if I kept the KH and
GH around 4 and do the usual Bi-weekly 25% water change, that not too much
Na+ and Cl- would sneak in and build up in concentration.  Of course, if a
could find a cheap (~$10) test kit for chlorides, this approach would be a
lot less risky.

Ron Wozniak  Allentown PA, USA
rjwozniak at lucent_com