trader_4 wrote, on Tue, 24 Jun 2014 06:55:11 -0700:

Let's continue the math. A gallon by your calculations costs $3.32.
It has 12% chlorine. A gallon weighes about 8.3 lbs, so you're getting
1 lb of chlorine for $3.32.

My fault. I should have provided more details about the percentage.

This lousy issue of % Available Chlorine vs. Trade % (volume % Available Chlorine)
vs. % of product (weight % of product) is extremely confusing to me; but,
it makes a huge difference in the calculations of cost for chlorine!

Specifically, bleach percentages are listed by weight, such that 6% bleach
is 6% by weight, or 5.7% available chlorine. However, the HASA liquid chlorine
is listed by trade percentage, so 12.5% trade chlorine is 11.6% available chlorine.

In both cases the actual strength varies with age where the turnover in
the HASA chlorine is extremely fast (they go through a few pallets a day!)
while the turnover in bleach is dismal by way of comparison (however, the
*lower* the percentage of chlorine, the longer it lasts (which seems counter
intuitive, to me, but I have confirmed this will phone calls to Clorox folks).

Given the percentage confusion above, we can then add solid equations,
to finally get these generic equations for calculating the true cost of
sanitizing chlorine for all three types:

a) liquid chlorine:
$cost/gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine

b) liquid bleach:
$cost/gallon x 1gallon/9.0pounds x 1/5.7% by wt available chlorine

c) solids:
$cost/pound x 1/??% by wt available chlorine, as listed on the container

(assume 36% if it's not listed, which is what I've found out by calling
*every* manufacturer who didn't list the percentage! They're trying to
hide a lousy number every time!).