Perhaps we are confusing alkalinity with basic. Alkalinity is the measure of
a solution's ability to resist change in pH. Water which is measured "soft"
is typically lacking in carbonate ions. Those carbonates are a chief factor
in adding to a solution's "Alkalinity"

Alkaline is NOT a synonym for Basic. Basic is the opposite of Acidic.

Water could very easily be soft and basic. Add NaOH to pure water and get a
very basic solution. It would however be very soft.

http://bcn.boulder.co.us/basin/data/.../info/Alk.html

Alan Ruben
www.bostonaquariumsociety.org



"David Martin" wrote in message
...
Thanks, Marcus!

Oddly enough, your previous post never appeared; at least as far as my PC
was concerned. However, it did appear in Jim Brown's reply. Lost in
Cyberspace. :-)

I have been told that it is not possible to have water which is both soft
and alkaline. There would seem to be good evidence that it is possible.

I'll take a look at the links.

David




"Marcus Fox" wrote in
message ...
I figure that this data can serve as a useful starting point for
setting
up
water chemistry.

How do I interpret these?
Total Hardness CaCO3 mg/L 30 - 34
Alkalinity CaCO3 mg/L 15 - 20
pH pH Units 6.5 - 8.5
I understand the pH part, and mine is high sevens. How about the rest?
Is
that hard, medium, or soft water? Soap lathers well, so it can't be
very
hard.

Sorry, I replied earlier, but didn't answer your question. Basically 1
mg/L
is 1 ppm. The information below is taken from
http://faq.thekrib.com/begin-chem.html, which you may like to read,
along
with all the other pages at http://faq.thekrib.com. Looking at the
table,
it
would appear that your water is very soft.

Marcus

*********************************

Water hardness follows the following guidelines. The unit dH means
"degree
hardness", while ppm means "parts per million", which is roughly
equivalent
to mg/L in water. 1 unit dH equals 17.8 ppm CaCO3. Most test kits give
the
hardness in units of CaCO3; this means the hardness is equivalent to
that
much CaCO3 in water but does not mean it actually came from CaCO3
General Hardness

0 - 4 dH, 0 - 70 ppm : very soft
4 - 8 dH, 70 - 140 ppm : soft
8 - 12 dH, 140 - 210 ppm : medium hard
12 - 18 dH, 210 - 320 ppm : fairly hard
18 - 30 dH, 320 - 530 ppm : hard