UPDATE: Here is the final summary of the cost equations, to date ...

Fact Sheet on Cyanuric Acid and Stabilized Chlorine Products

1. Liquid chlorine at 12.5% trade percentage available chlorine by volume
(aka 10.78% available chlorine by weight)
(aka 11.31% weight percentage of sodium hypochlorite):
price per pound of available chlorine =
$price/gallon liquid x 1gallon liquid/9.7pounds liquid x 100 pounds liquid/10.78 pounds available chlorine


2. Bleach at 8.25% weight percentage of sodium hypochlorite
(aka 9.08% trade % available chlorine by volume)
(aka 7.86% available chlorine by weight):
price per pound of available chlorine =
$price/gallon liquid x 1gallon liquid/9.0pounds liquid x 100 pounds liquid/7.86 pounds available chlorine


3. Bleach at 6% weight percentage of sodium hypochlorite
(aka 6.17% trade % available chlorine by volume)
(aka 5.71% available chlorine by weight):
price per pound of available chlorine =
$price/gallon liquid x 1gallon liquid/9.0pounds liquid x 100 pounds liquid/5.71 pounds available chlorine = price per pound of available chlorine


4. Sodium Dichloro-s-Triazinetrione, anhydrous at 99% by weight
(available chlorine is 64% by weight, or as listed on the package):
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/64 pounds available chlorine

5. Sodium Dichloro-s-Triazinetrione dihydrate at 99% by weight
(available chlorine is 55% by weight, or as listed on the package):
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/55 pounds available chlorine

Note: This is sometimes listed as Sodium Dichloro-s-Triazinetrione,
typically 85% by weight with 14% locked up as water, but the available
chlorine is still 55%)

6. Trichlor from Home Depot & Leslie's Pool at 99% by weight
(aka trichloroisocyanuric acid, listed at 90% available chlorine)
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/90 pounds available chlorine

7. Trichlor from Costco & Lowes at 95% by weight
(aka trichloroisocyanuric acid, listed at 85% available chlorine)
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/85 pounds available chlorine

8. Shock Plus 4 in 1 pool shock, Aqua Chem Costco item #175121, 24 pack
(where available chlorine is 35.6%, confirmed by phone 800-252-7665
and 800-859-7946 technical support for 'product code' 22112AQU).
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/35.6 pounds available chlorine
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Note1: The Costco #175121 product is labeled EPA REG No 67262-27,
Here is the EPA lookup for that product:
http://pesticideinfo.org/Detail_Prod...ST_NR=0672 62
According to that page, the product is 58.2% Sodium dichloro-s-triazinetrione.
So compared to Dichlor dihydrate, which is 85% Sodium dichloro-s-triazinetrione
(i.e. not including the dihydrate), the Costco product is 68.5% of what you
would get with a normal Dichlor dihydrate product.

This 68.5% is purity relative to 99% pure Dichlor Dihydrate product,
NOT an absolute % Available Chlorine. The % Available Chlorine of 100%
pure Dichlor Dihydrate is 55.4% while the typical 99% pure product is
54.9% (i.e. 55%). 0.99*55.4%*0.685 = 37.6% so it's close to the 35.6%
the company quotes when you call them in Georgia.
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Note2: Sometimes, Dichlor Dihydrate available chlorine is shown as 56%
(even though 100% pure product would be 55.4% and 99% pure product
would be 54.8%), possibly because there may be some anhydrous Dichlor
mixed in with the Dichlor Dihydrate (manufacturing processes are not
perfect). Also, most confusing, is that sometimes they leave out the
"dihydrate" in the ingredients even though it is really there.
The easiest way to tell is by looking at the % available chlorine.
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Note3: Although the ingredients may say "Sodium Hypochlorite" at
12.5% on a bottle of chlorinating liquid, which would normally
imply that to be the weight percent of sodium hypochlorite; however,
in practice, it's the Trade % that is listed ast 12.5% on the bottle
of liquid chlorine. It's very confusing and really hard to know the
truth. Also, higher chlorine levels degrade faster, which is why
most don't worry much about it. Look at this link for a product
specification for "12.5 Trade Percent Available Chlorine"
chlorinating liquid with 10.55 - 10.8 Weight % Available Chlorine
and 11.0 - 11.3 Weight % Sodium Hypochlorite.
http://www.odysseymanufacturing.com/product_spec.htm
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