"Mike Ruskai" wrote in message
...
On or about Thu, 10 May 2007 00:14:04 -0700 did "SJF"
dribble thusly:


"Mike Ruskai" wrote in message
. ..
I've recently had a water softener put in, and I'm looking to
configure it for the most efficient salt usage with an appropriate
regeneration time.

There is a calculator which you may use to check your calculations at --

http://www.qualitywaterassociates.com/sizing.php

This calculator exactly matches my results for 6lb/ft^3 of salt, so
that helps.


If you use KCl rather than NaCl, the salt dosage should be increased about
27% at each recharge.

That seems a bit much. I'll try to verify that number, but at least
it's something to go on.

Thanks.
--
- Mike

Ignore the Python in me to send e-mail.

OK Mike. I had to buy a new unit (Fleck 5600) a year ago and went through
all the calculations. Tedious, and the question comes up as to achieving
the best efficiency consistent with convenience. There are tradeoffs and
the different annual cost of salt turned out to be not very significant to
me as one approached the highest efficiency settings. I do not use KCl
which would magnify the difference, of course.

For any operating cycle, there is generally one day at the end of the cycle
that results in a loss of usable capacity. Particularly, if you have a
water supply of varying hardness, the margin for error must be set
liberally. This affects the overall efficiency and suggests that the
problem can be reduced by going to less frequent recharges. So there are
countervailing forces working on the efficiency. I expect that if you have
a low salt recharge that would normally run less than a week, you have lost
any efficiency that might be achieved by a short cycle. I settled on
something a bit above what is sometimes considered optimum. Good solution
for me. In California, there is a lot of concern about environmental
factors -- return of salt to groundwater -- and there are local regulations
aiming a the salt efficient settings. Sometimes, these things go a bit far.

On the KCl vs. NaCl thing --

I took the number from an unremembered source I considered probably
reliable. Checking, I find that the molecular weight of KCl is 27% greater
than that of NaCl so you would need the extra weight of salt to provide an
equivalent recharge. Since the solubility of KCl at 20 degrees Centigrade
is essentially the same as for NaCl, the water used for brining would need
to be increased 27% to get the extra salt.

For a long retired, and pretty rusty engineer, this exploration into water
softener technology was a pretty interesting exercise -- another where a
perfect answer is not in the cards. As Yogi Berra said, "If you come to a
fork in the road, take it."

SJF