SMS turned me on to the "Pool Store" in Saratoga, which runs a "special"
all the time on HASA 12% liquid chlorine (I buy 16 gallons at a time),
which has the following math, if interested.

HISTORY:
It used to be "buy one case, get one case free", which was pretty simple
because one case of 4 gallons was $18.40 + 8.75% sales tax added $1.61
which made each gallon $4.60 + ~$ 0.41 tax ~= $5.00/gallon out the door
if you only bought one case, but, with the free case, that added just
the ~$1.61 tax (California makes you pay tax on free stuff), so for 8
gallons, it used to be simple at $18.40 + 2($1.61) = $21.62/8 = $2.70/gallon.

CURRENT:
Now, it's no longer that simple.

It's still $18.40/case + 8.75% tax for one case, but if you buy two cases,
the price has changed to "buy 6 gallons get 2 free", whose math turns out
to then be 6 gallons x $4.60 each gallon + $0.41 tax each gallon = $30.00,
plus tax on the two free gallons at $0.41 each, which turns out to = $30.82
for 8 gallons, or ~$3.85/gallon of 12% HASA liquid chlorine.

But, you always get a card for "buy 11, get 1 free" at the store, so,
you end up subtracting $4.60 from that on every second visit, so, on that
second visit, you end up subtracting $4.60 but adding $0.41 tax, which
nets in a second trip cost of $30.82 - $4.60 + $0.41 = $26.63, which
then comes to $3.32/gallon on that second trip.

If you average the first-trip cost of $3.85/gallon & the second-trip
cost of $3.32/gallon, which is about $3.59/gallon, overall.

On Monday, June 23, 2014 5:26:06 PM UTC-4, DannyD. wrote:
SMS turned me on to the "Pool Store" in Saratoga, which runs a "special"

all the time on HASA 12% liquid chlorine (I buy 16 gallons at a time),

which has the following math, if interested.



HISTORY:

It used to be "buy one case, get one case free", which was pretty simple

because one case of 4 gallons was $18.40 + 8.75% sales tax added $1.61

which made each gallon $4.60 + ~$ 0.41 tax ~= $5.00/gallon out the door

if you only bought one case, but, with the free case, that added just

the ~$1.61 tax (California makes you pay tax on free stuff), so for 8

gallons, it used to be simple at $18.40 + 2($1.61) = $21.62/8 = $2.70/gallon.



CURRENT:

Now, it's no longer that simple.



It's still $18.40/case + 8.75% tax for one case, but if you buy two cases,

the price has changed to "buy 6 gallons get 2 free", whose math turns out

to then be 6 gallons x $4.60 each gallon + $0.41 tax each gallon = $30.00,

plus tax on the two free gallons at $0.41 each, which turns out to = $30.82

for 8 gallons, or ~$3.85/gallon of 12% HASA liquid chlorine.



But, you always get a card for "buy 11, get 1 free" at the store, so,

you end up subtracting $4.60 from that on every second visit, so, on that

second visit, you end up subtracting $4.60 but adding $0.41 tax, which

nets in a second trip cost of $30.82 - $4.60 + $0.41 = $26.63, which

then comes to $3.32/gallon on that second trip.



If you average the first-trip cost of $3.85/gallon & the second-trip

cost of $3.32/gallon, which is about $3.59/gallon, overall.

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.

Tablet form is available many places for about $80 for a 40lb pail.
IT's 90% chlorine, so you're getting 36 pounds of chlorine. That's
$2.22 a pound. Add tax of 7%, and it's $2.38. The liguid is
40% more expensive. Not to mention harder to haul around, you have
to add it every couple days by hand, versus one bucket, where you grab
7 tablets, put them in a floating dispenser and you're good for a week.

If you have issues with too much stablizer building up, then I can
see using chlorine. But here in northeast, the stabilizer works out
just right, and it's free. Stabilizer isn't cheap, so factor that
you need to buy that too when using liquid and
using liquid chlorine would be even more expensive. And it's also a
PIA to get stabilizer to disolve too. With the tabs, it's cheap, no
fuss, no muss.

"DannyD." wrote in
:

Subject: Actual price/gallon for 12% Hasa Pool Chlorine (for SMS and
the Silicon Valley) From: "DannyD."
Newsgroups: alt.home.repair

SMS turned me on to the "Pool Store" in Saratoga, which runs a
"special" all the time on HASA 12% liquid chlorine (I buy 16 gallons
at a time), which has the following math, if interested.


I'm not sure what you have there. Can you post some pics?

Thanks

On Monday, June 23, 2014 5:26:06 PM UTC-4, DannyD. wrote:
CURRENT:

Now, it's no longer that simple.

No kidding. You got it completely wrong.

Here's a better calculation from someone who appears to know what they
are doing.

On Tue, 24 Jun 2014 06:55:11 -0700 (PDT), trader_4
wrote in


Tablet form is available many places for about $80 for a 40lb pail.
IT's 90% chlorine, so you're getting 36 pounds of chlorine. That's
$2.22 a pound. Add tax of 7%, and it's $2.38. The liguid is
40% more expensive. Not to mention harder to haul around, you have
to add it every couple days by hand, versus one bucket, where you grab
7 tablets, put them in a floating dispenser and you're good for a week.

If you have issues with too much stablizer building up, then I can
see using chlorine. But here in northeast, the stabilizer works out
just right, and it's free. Stabilizer isn't cheap, so factor that
you need to buy that too when using liquid and
using liquid chlorine would be even more expensive. And it's also a
PIA to get stabilizer to disolve too. With the tabs, it's cheap, no
fuss, no muss.

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!).

Zaky Waky wrote, on Tue, 24 Jun 2014 14:47:03 +0000:

I'm not sure what you have there. Can you post some pics?

I'm not sure what you want a picture of?

Here is the pool store that sells the HASA liquid chlorine:
http://www.yourpoolguys.com/

Here is a screenshot of the coupon they perennially offer:
http://www.valpak.com/coupons/printa...ool-Guys/24074

Here is a photo of the 8 gallons of HASA chlorine I buy:
http://www5.picturepush.com/photo/a/...0/13401918.jpg

The price is the best I can calculate for chlorine, given prices
at Leslie's Pool, Costo, Lowes, Home Depot, Safeway, and Orchard
Supply (OSH).

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

If you have issues with too much stablizer building up, then I can
see using chlorine. But here in northeast, the stabilizer works out
just right, and it's free.

You bring up a very good point about the stabilizer!

Every year I empty my pool (a bit under 40K gallons) and fill it back up
again, so, I have to add the cyanuric acid (CYA) stabilizer.

I used to add about 15 pounds of the *granules* to bring up the CYA from
0ppm to about 50ppm (we have a *lot* of sun out here), but this year I
added 15 pounds of the CYA *powder* which is *very easy* to do once you
know how!

I'll never use the granules ever again.

The powder is available from *any* pool store that buys liquid chlorine
from HASA (which is common out here in California), and they sell it in
any desired amount at the *same price* as they sell the CYA granules.

So, in a single sitting (about an hour), I can bring up a pool from
zero PPM to 50ppm CYA, so that the liquid chlorine has a chance of lasting
in this perennial sunlight.

As you noted, all the solid pucks and most of the "shock" powders also
contain CYA, and I also use them (when appropriate, e.g., when I go
on vacation), so, there is nothing wrong with the "slow" method either.

One caution though is that it takes *technique* to distribute the CYA
powder, because it won't work in a sock like the granules do, but, once
you know the technique, it's even easier than using CYA granules, and
certainly far cheaper than the so-called "liquid CYA" you can buy in
the pool stores.

VinnyB wrote, on Tue, 24 Jun 2014 09:57:58 -0500:

No kidding. You got it completely wrong.

I think these are the equations, are they not?

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

DannyD. wrote, on Tue, 24 Jun 2014 20:32:18 +0000:

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

I have used all three types of chlorine:
https://c1.staticflickr.com/3/2908/1...5922732f_b.jpg

Assuming the HASA liquid chlorine averaged $3.59/gallon after all the
value-pack coupon and buy-11-get-one-free complicating shenanigans:

The equation for liquid chlorine is:
$cost/gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine

So that's:
$3.59/gallon x 1gallon/9.7pounds x 100/10.8 = $3.43/pound of available Cl

By way of liquid chlorine local (Silicon Valley) comparison:
Home Depot = $6.86/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $3.27/pound of available Cl
Lowes = $6.90/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $3.29/pound of available Cl
Leslie = $10.49/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $5.01/pound of available Cl

Comparing the Dichlor, we get:
Leslies = $122/40 pounds * 100/55 pounds = $5.55/pound of available Cl
Lowes = $70/22.5 pounds * 100/56 pounds = $5.56/pound of available Cl
Home Depot = $80/22.5 pounds * 100/56 pounds = $6.35/pound of available Cl
Costco = $55/24 pounds * 100/36 = $6.37/pound of available Cl

For Trichlor, we get:
Home Depot = $75/37.5 pounds * 100/90 pounds = $2.22/pound of available Cl
Costco = 84.79/40 pounds * 100/84.65 pounds = $2.50/pound of available Cl
Lowes $75/35 pounds * 100/85 pounds = $2.52/pound of available Cl[/b]
Leslies = $80/35 pounds * 100/90 pounds = $2.54/pound of available Cl

For Calcium hypochlorite, we get:
Leslies = $107.19/25 pounds * 100/73 pounds = $5.87/pound of available Cl

So, the best price for available chlorine (excluding the fact it raises the
CYA), seems to be the Home Depot Trichlor, or (if you don't want to raise
CYA), the Home Depot liquid chlorine (assuming it's fresh).

On Tuesday, June 24, 2014 3:27:13 PM UTC-4, DannyD. wrote:
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.



Wow, like 12.5 vs 11.6 really changes it materially. Actually, I thought
the liq pool chlorine was typically 12%.




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!).


And after all that, the liquid chlorine is still 40% more
expensive than trichlor. And with trichlor, you bring home
one 40 lb pail that lasts a season. You grab 6 tablets, put them
in the floating duck once a week. Less expensive and no shlepping
36 gallons of liq chlorine in jugs around in the car and
then putting it in every couple of days.

On Tuesday, June 24, 2014 5:22:25 PM UTC-4, DannyD. wrote:
DannyD. wrote, on Tue, 24 Jun 2014 20:32:18 +0000:



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



I have used all three types of chlorine:

https://c1.staticflickr.com/3/2908/1...5922732f_b.jpg



Assuming the HASA liquid chlorine averaged $3.59/gallon after all the

value-pack coupon and buy-11-get-one-free complicating shenanigans:



The equation for liquid chlorine is:

$cost/gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine



So that's:

$3.59/gallon x 1gallon/9.7pounds x 100/10.8 = $3.43/pound of available Cl



By way of liquid chlorine local (Silicon Valley) comparison:

Home Depot = $6.86/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $3.27/pound of available Cl

Lowes = $6.90/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $3.29/pound of available Cl

Leslie = $10.49/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $5.01/pound of available Cl



Comparing the Dichlor, we get:

Leslies = $122/40 pounds * 100/55 pounds = $5.55/pound of available Cl

Lowes = $70/22.5 pounds * 100/56 pounds = $5.56/pound of available Cl

Home Depot = $80/22.5 pounds * 100/56 pounds = $6.35/pound of available Cl

Costco = $55/24 pounds * 100/36 = $6.37/pound of available Cl



For Trichlor, we get:

Home Depot = $75/37.5 pounds * 100/90 pounds = $2.22/pound of available Cl

Costco = 84.79/40 pounds * 100/84.65 pounds = $2.50/pound of available Cl

Lowes $75/35 pounds * 100/85 pounds = $2.52/pound of available Cl[/b]

Leslies = $80/35 pounds * 100/90 pounds = $2.54/pound of available Cl



For Calcium hypochlorite, we get:

Leslies = $107.19/25 pounds * 100/73 pounds = $5.87/pound of available Cl



So, the best price for available chlorine (excluding the fact it raises the

CYA), seems to be the Home Depot Trichlor, or (if you don't want to raise

CYA), the Home Depot liquid chlorine (assuming it's fresh).

$2.22 vs $3.27 So liquid chlorine is 47% more expensive than trichlor. The calculations I presented liquid chlorine was 40% more. 40%, 47% it makes not
a nipple's worth of difference.

trader_4 wrote, on Tue, 24 Jun 2014 16:02:51 -0700:

Wow, like 12.5 vs 11.6 really changes it materially.
Actually, I thought the liq pool chlorine was typically 12%.

I'm sorry if the implication was that it changed the results
by a lot. It doesn't, I agree. I was just being precise, but,
as we all know, the *age* of the liquid chlorine and exposure
to the elements can make a big difference in the levels.

So, your numbers are as good as mine, I agree. I never meant
to intimate otherwise.

And after all that, the liquid chlorine is still 40% more
expensive than trichlor.

This is a good point.
The liquid chlorine, I admit, is a pain.
Plus, it raises the pH (which is a different pain).
And it's a long drive for me to get the HASA stuff, which I
use a lot of:

But, I also use the trichlor!
https://c1.staticflickr.com/3/2908/1...5922732f_b.jpg

And with trichlor, you bring home one 40 lb pail that lasts a season.

I use a few hundred pounds in some seasons, so the added CYA
is a problem. How much of a problem the CYA becomes is based
more on the leaks I repair (right now I have most repaired).

You grab 6 tablets, put them in the floating duck once a week.
I have four floaters, plus I use liquid chlorine, so, it's not
as inexpensive as you intimate, but I also have a huge pool.
https://c2.staticflickr.com/4/3678/1...18e5582b_b.jpg

Less expensive and no shlepping 36 gallons of liq chlorine in
jugs around in the car and then putting it in every couple of days.

I use both the trichlor pucks and the liquid chlorine:
https://c1.staticflickr.com/3/2908/1...5922732f_b.jpg

Both have their problems.
a) The trichlor adds CYA, which, after a while, is a bad thing
(as you always need to keep FC above the CYA levels).
b) The liquid chlorine is difficult to handle as I buy 16 gallons
at a time, and it's a royal pain to use.

The pool is pretty deep, as pools go:
https://c2.staticflickr.com/4/3750/1...bd17ae83_b.jpg

trader_4 wrote, on Tue, 24 Jun 2014 16:08:50 -0700:

$2.22 vs $3.27 So liquid chlorine is 47% more expensive than trichlor. The calculations I presented liquid chlorine was 40% more. 40%, 47% it makes not
a nipple's worth of difference.

I think you are correct that, at the current prices, the HASA liquid chlorine
is substandard to the Costco or Home Depot trichlor pucks, when it comes to
sheer price per chlorinating power.

Here are, I think, the overall equations for each type:
liquid chlorine:
$cost/gallon x 1gallon/9.7pounds x 1/10.78% available chlorine (by weight) = price per pound of available chlorine

liquid bleach:
$cost/gallon x 1gallon/9.0pounds x 1/5.7% available chlorine (by weight) = price per pound of available chlorine

chlorine solids:
$cost/pound x 1/xx% available chlorine (by weight) = price per pound of available chlorine

On Tuesday, June 24, 2014 7:52:50 PM UTC-4, DannyD. wrote:
trader_4 wrote, on Tue, 24 Jun 2014 16:02:51 -0700:



Wow, like 12.5 vs 11.6 really changes it materially.

Actually, I thought the liq pool chlorine was typically 12%.



I'm sorry if the implication was that it changed the results

by a lot. It doesn't, I agree. I was just being precise, but,

as we all know, the *age* of the liquid chlorine and exposure

to the elements can make a big difference in the levels.



So, your numbers are as good as mine, I agree. I never meant

to intimate otherwise.



And after all that, the liquid chlorine is still 40% more

expensive than trichlor.



This is a good point.

The liquid chlorine, I admit, is a pain.

Plus, it raises the pH (which is a different pain).

And it's a long drive for me to get the HASA stuff, which I

use a lot of:



But, I also use the trichlor!

https://c1.staticflickr.com/3/2908/1...5922732f_b.jpg



And with trichlor, you bring home one 40 lb pail that lasts a season.



I use a few hundred pounds in some seasons, so the added CYA

is a problem. How much of a problem the CYA becomes is based

more on the leaks I repair (right now I have most repaired).



You grab 6 tablets, put them in the floating duck once a week.

I have four floaters, plus I use liquid chlorine, so, it's not

as inexpensive as you intimate, but I also have a huge pool.

https://c2.staticflickr.com/4/3678/1...18e5582b_b.jpg



Four floaters? Hundreds of pounds a season? Your season is longer,
but something isn't right here. 48,000 gallon pool
here, just one floater. One 40 pound pail of Trichlor lasts from
mid-May to early Sept, about 4 months.




Less expensive and no shlepping 36 gallons of liq chlorine in

jugs around in the car and then putting it in every couple of days.



I use both the trichlor pucks and the liquid chlorine:

https://c1.staticflickr.com/3/2908/1...5922732f_b.jpg



Both have their problems.

a) The trichlor adds CYA, which, after a while, is a bad thing

(as you always need to keep FC above the CYA levels).

b) The liquid chlorine is difficult to handle as I buy 16 gallons

at a time, and it's a royal pain to use.



The pool is pretty deep, as pools go:

https://c2.staticflickr.com/4/3750/1...bd17ae83_b.jpg

How many gallons?

trader_4 wrote, on Wed, 25 Jun 2014 02:51:25 -0700:

How many gallons?
40K

Four floaters? Hundreds of pounds a season?
Your season is longer,
but something isn't right here.

The sun is brutal here, so I both add isocyanuric acid
(CYA) powder (not granules) and use the floaters until
the CYA level gets around 60 to about 80 ppm, then I have
to pull the floaters, and use liquid chlorine from that
point onward, until I empty the pool again.

DannyD. wrote, on Wed, 25 Jun 2014 13:35:56 +0000:

The sun is brutal here, so I both add isocyanuric acid
(CYA) powder (not granules)

BTW, adding the special CYA *powder* is necessary under circumstances
when you can't run the equipment after having refilled the pool (due
to water levels taking weeks to rise given slow well refilling) and
given a very high sun load (California).

To be sure, adding the *powder* is easy, but all normal methods will
fail miserably, because once the powder gets wet, it *instantly* turns
into a solid brick! (I've never seen anything "set" so fast!)

Bearing in mind that CYA powder will do the same thing in your lungs, if
it ever gets that far, after a few failed experiments, I was able devise
a CYA powder distribution method that *easily* brings a pool from 0 ppm
CYA to about 40 ppm in a single sitting, with *no visible CYA residue*.

Here's a picture of the iso cyanuric acid powder:
https://c2.staticflickr.com/4/3754/1...f9945a46_b.jpg

Here's a picture of my starting point:
https://c1.staticflickr.com/3/2921/1...a42f6d2f_b.jpg

The first thing I did was sift the powder into a 5-gallon bucket of water:
https://c1.staticflickr.com/3/2935/1...49c388f9_b.jpg

If I didn't swish the water, and just let the CYA settle, this is
what happened at the bottom of the bucket:
https://c2.staticflickr.com/4/3774/1...1b2bb601_b.jpg

So, I learned to swish the water while shaking the powder over the
skimmer net into the bucket of water.
https://c2.staticflickr.com/4/3717/1...d6f33721_b.jpg

Then I poured the water into another bucket:
https://c1.staticflickr.com/3/2905/1...69793809_b.jpg

And, as I poured, I filtering out any sediment with a skimmer net:
https://c2.staticflickr.com/4/3714/1...6b420a5c_b.jpg

Over time, I learned, the more I swished, the less sediment I filtered:
https://c2.staticflickr.com/6/5191/1...0be45d05_b.jpg

Until I got to a point where four or five 8-ounce cups of the powder
would easily go into a five-gallon bucket of water:
https://c2.staticflickr.com/4/3665/1...6e28031d_b.jpg

Then, I simply poured the suspended-particle CYA "milk" slurry
into the pool:
https://c1.staticflickr.com/3/2901/1...c71a9dd0_b.jpg

The lovely clouds of suspended CYA particles in the water were
a beautiful sight to see (these clouds are *in* the water!):
https://c2.staticflickr.com/4/3799/1...6f8fb243_b.jpg

By way of failed experimentation, simply shaking the CYA powder
over the pool with a skimmer net fails if there is any wind,
as the powder blows away; and it fails the moment you accidently
get the powder wet (which turns it into an instant brick)
https://c2.staticflickr.com/4/3793/1...3920d46e_b.jpg

And, even if you're successful at shaking the powder over the pool
on a calm day, the powder floats on the top of the water like an
island, due to its propensity to form clumps:
https://c2.staticflickr.com/6/5113/1...9d55434f_b.jpg

But, I'm happy to report that the double-bucket swishing filter
method works just fine, and it's very easy and satisfying to do!
https://c2.staticflickr.com/6/5517/1...f36835bd_b.jpg

Here is another picture of the lovely cloud of CYA dispersing
throughout the pool, with each CYA particle surrounded by water:
https://c2.staticflickr.com/4/3723/1...931740a1_b.jpg

IMHO, this is the easiest, cheapest way, to add CYA to your pool
if you recently refilled it, and if you have a huge sun load, like
I do (which will murder you in chlorine costs otherwise):
https://c2.staticflickr.com/6/5571/1...f9853124_b.jpg

On Wed, 25 Jun 2014 13:35:56 +0000 (UTC), "DannyD."
wrote:

The sun is brutal here, so I both add isocyanuric acid
(CYA) powder (not granules) and use the floaters until
the CYA level gets around 60 to about 80 ppm, then I have
to pull the floaters, and use liquid chlorine from that
point onward, until I empty the pool again.

I was hoping you would mention the % of concentrated Clorox un-scented
bleach :-\

There was a link posted here, it spoke of testing after sun-down,
etc. (twice a day, once after sun-up Sort of a way to find
fluctuations in the pool chemistry.

On Wednesday, June 25, 2014 9:35:56 AM UTC-4, DannyD. wrote:
trader_4 wrote, on Wed, 25 Jun 2014 02:51:25 -0700:



How many gallons?

40K



Four floaters? Hundreds of pounds a season?

Your season is longer,

but something isn't right here.



The sun is brutal here, so I both add isocyanuric acid

(CYA) powder (not granules) and use the floaters until

the CYA level gets around 60 to about 80 ppm, then I have

to pull the floaters, and use liquid chlorine from that

point onward, until I empty the pool again.

With 4 floaters, isn't the chlorine through the roof?
There is plenty of full sun here in summer in the NYC area
and with a 48,000 gallon pool, 1 floater loaded with
about 7 tabs keeps the chlorine at about 2 PPM. If you
have 4 floaters going, then you're going to be adding
CYA at 4X the typical rate, so I'm not surprised you
have an excess CYA problem. The question is why you
need so much chlorine? I've never seen a pool with
more than one floating dispenser, let alone four.

Oren wrote, on Wed, 25 Jun 2014 07:24:12 -0700:

I was hoping you would mention the % of concentrated
Clorox un-scented bleach :-\

Hi Oren,

Huckleberries are, um, I mean bleach is a strange beast indeed, which,
I admit, is confusing because, while chlorinating liquid is usually
sold by *trade percentage*, in contrast, a regular bleach is usually
sold by *weight percentage* of product (i.e., of sodium hypochlorite).

So 8.25% bleach (sold by weight % of sodium hypochlorite) is only
7.86% available chlorine (by weight), and, assuming a 1.10 g/ml density,
this is 9.08% trade percentage (i.e., % Available Chlorine by volume).

Similarly, a typical 6% bleach is 6% sodium hypochlorite by weight, which
is only 5.7% available chlorine.

Hence, the two equations:
1. Cost per pound of available chlorine for liquid chlorine:
$cost/gallon x 1gallon/9.7pounds x 100pounds of liquid/10.78pounds available chlorine

2. Cost per pound of available chlorine for liquid bleach:
$cost/gallon x 1gallon/9.0pounds x 100pounds of liquid/5.7 pounds available chlorine

Sometimes things are just complicated.

trader_4 wrote, on Wed, 25 Jun 2014 08:06:58 -0700:

With 4 floaters, isn't the chlorine through the roof?

I understood everything you imply, as I am familiar with
the increasing ratio of CYA to target free chlorine level
as per this common table:

(Stabilizer) (Minimum FC) (Target FC) (Shock FC)
20 2 3 10
30 2 4 12
40 3 5 16
50 4 6 20
60 5 7 24
70 5 8 28
80 6 9 31
90 7 10 35
100 7 12 39
etc.

There is plenty of full sun here in summer in the NYC area
and with a 48,000 gallon pool, 1 floater loaded with
about 7 tabs keeps the chlorine at about 2 PPM.

I actually only have about 50 ppm CYA, even with adding the
powder, which means I need to target Free Chlorine at 6 ppm.

The question is why you need so much chlorine?

I realize it's not often stated at the pool store, but,
the chlorine number is wholly useless without the associated
CYA value.

For example, with your 2ppm of free chlorine, if you had
a 40 ppm CYA, you'd already be below the minimum, and far
below the target chlorine levels for your pool (based on
my read of the chart above).

I can only hope, for your sake, that your CYA is at or
below 30ppm, which, for a sunny area out here, would not
be enough stabilizer.

I've never seen a pool with more than one floating dispenser,
let alone four.

You haven't seen "my" pool!

Seriously though, I'm welcome and open to ideas, as I can't
seem to keep chlorine in this pool, even though the biological
load is nearly zero (nobody even swims in it lately).

DannyD. wrote, on Wed, 25 Jun 2014 20:12:23 +0000:

regular bleach is usually
sold by *weight percentage* of product (i.e., of sodium hypochlorite).

From the net ...

So, for example, 12.25% Trade Percentage is % Available Chlorine by volume
which is is 10.78% Available Chlorine by weight assuming 1.16 g/ml density
and is 11.31% sodium hypochlorite by weight.

Weight % Available Chlorine = Trade % / Specific Gravity
= (Weight % NaOCl) * Cl2_g_mole / NaOCl_g_mole = (Weight % NaOCl) * 0.9525

So Weight % NaOCl = 1.05 * Weight % Available Chlorine

The divisor in those equations calculating pounds of available chlorine
is "% Available Chlorine (by weight)".

While chlorinating liquid is usually sold by Trade %,
the percentage for regular bleach is usually weight % of product
(i.e. sodium hypochlorite) so 8.25% bleach (weight % of sodium hypochlorite)
is 7.86% Available Chlorine (by weight) and assuming a 1.10 g/ml density
this is 9.08% Trade (% Available Chlorine by volume).

"DannyD." wrote in :

I understood everything you imply, as I am familiar with
the increasing ratio of CYA to target free chlorine level
as per this common table:


Can you post some pics of the labels of the chlorine that you are using?

On Wednesday, June 25, 2014 4:57:46 PM UTC-4, DannyD. wrote:
trader_4 wrote, on Wed, 25 Jun 2014 08:06:58 -0700:



With 4 floaters, isn't the chlorine through the roof?



I understood everything you imply, as I am familiar with

the increasing ratio of CYA to target free chlorine level

as per this common table:



(Stabilizer) (Minimum FC) (Target FC) (Shock FC)

20 2 3 10

30 2 4 12

40 3 5 16

50 4 6 20

60 5 7 24

70 5 8 28

80 6 9 31

90 7 10 35

100 7 12 39

etc.



I've never seen that table. What makes you think it's right?
If you look at the recommendations from the credible organizations,
pool standards organizations, health depts, etc, what I've seen is a recommended range of 1 -3,
with no adjustment for CYA. I know CYA has an effect, in the sense
that while it stabilizes it, it also lessens the sterilizing
effect if it gets too high. If you really need to hike the cholrine way up
there like that, it's strange that I don't see people doing it,
it's not mentioned in health dept guidelines for pools, etc.
I can tell you that 1 - 3 ppm has worked fine here for me for years
over a wide range of CYA levels. No water clarity, algae issues.




There is plenty of full sun here in summer in the NYC area

and with a 48,000 gallon pool, 1 floater loaded with

about 7 tabs keeps the chlorine at about 2 PPM.



I actually only have about 50 ppm CYA, even with adding the

powder, which means I need to target Free Chlorine at 6 ppm.



I think you're over doing that by 2X or 3X. That's why you're
going through hundreds of pounds of trichlor or endless gallons
of liquid chlorine. But it's your pool, if you
want to go by some chart instead of what works, that's up to you.





The question is why you need so much chlorine?



I realize it's not often stated at the pool store, but,

the chlorine number is wholly useless without the associated

CYA value.



If it's so critical then why do public health depts that state
levels for pools just list the levels as 1 -3? IDK of any that
say you need 6PPM or that 6PPM is even appropriate for a residential
pool period.



For example, with your 2ppm of free chlorine, if you had

a 40 ppm CYA, you'd already be below the minimum, and far

below the target chlorine levels for your pool (based on

my read of the chart above).



I think you're obsessed with one chart of unknown background and
ignoring that if it's so important, it would be part of the std
guidelines for pool operators. AFAIK, it's not. And using 1/3
the chlorie you use works fine here in my pool. I've had CYA at
70, chlorine at 2 or 3 and the water is clear, no algae, etc.




I can only hope, for your sake, that your CYA is at or

below 30ppm, which, for a sunny area out here, would not

be enough stabilizer.



I hope for the sake of your wallet that you reconsider.




I've never seen a pool with more than one floating dispenser,

let alone four.



You haven't seen "my" pool!



Well, I meant except yours.




Seriously though, I'm welcome and open to ideas, as I can't

seem to keep chlorine in this pool, even though the biological

load is nearly zero (nobody even swims in it lately).

It's not that you can't keep chlorine. It's that you have target
levels that are 2x - 3x too high.

A lot of this pool stuff is just handed down and a lot of it is
wrong. An example is the guideline that you should move the
volume of whatever the pool is through the filter system every day.
Really? The pool in the shade, the pool with a bunch of kids, the
pool in the sun, the pool that's used only one day a week, the pool
where it's windy and debris is blowing in, all have the same reqt?
I've found I can easily get by with half that filtering and it works.

This isn't rocket science, you can experiment and find out what happens.

Zaky Waky wrote, on Wed, 25 Jun 2014 21:30:36 +0000:

Can you post some pics of the labels of the chlorine that you are using?

Here is a picture of the chlorine "I" am using (Costco tablets & HASA liquid):
https://c2.staticflickr.com/6/5527/1...e66fd6c3_c.jpg

But, here is a more complete explanation of what *you* might find on the labels:

1. Liquid chlorine at 12.25% trade percentage available chlorine by volume (aka 10.78% available chlorine by weight, aka 11.31% weight percentage of sodium hypochlorite):
$cost/gallon liquid x 1gallon liquid/9.7pounds liquid x 100 pounds liquid/10.78 pounds available chlorine = price per pound of available chlorine

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

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

4. Solids & powders (available chlorine is as listed on the package):
$cost/pound solid x 100 pounds solid/?? pounds available chlorine = price per pound of available chlorine

Where the demominator for 99% by weight Sodium Dichloro-s-Triazinetrione, anhydrous, is 64.
And, where the denominator for 99% by weight Sodium Dichloro-s-Triazinetrione Dihydrate is 55
(which is the same chemical as Sodium Dichloro-s-Triazinetrione, typically 85% by wt & 14% water,
available chlorine 55%). But, the denominator can be as low as 36 for certain formulations
(e.g., Costco item #175121, aqua chem Shock Plus 4 in 1 pool shock 24 pack, EPA REG No 67262-27
telephone 800-252-7665).

For trichlor aka trichloroisocyanuric acid or richloro-s-triazinetrione, the available chlorine
varies by weight as listed on the package):
a. Home Depot & Leslie's Pool 99% trichlor is listed as 90% available chlorine.
b. Lowes 95% trichlor is listed as 85% available chlorine.
c. Costco 94.05% trichlor is listed as 84.65% available chlorine.

Note: 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.

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

I've never seen that table.
What makes you think it's right?

While it stands to logic in that the more stabilizer you have, the more
free chlorine you need to maintain its effectiveness, I didn't make that
table up.

The original Chlorine/CYA "Best Guess" chart was developed by Ben Powell.
Richard Falk had refined and expanded on that original to produce the
Chlorine/CYA Chart by Chem Geek as described he
http://www.troublefreepool.com/threa...rine-CYA-Chart

The point is that most people don't even realize that the free chlorine
that they need depends on the existing CYA level that they have!

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

what I've seen is a recommended range of 1 -3,
with no adjustment for CYA. I know CYA has an effect, in the sense
that while it stabilizes it, it also lessens the sterilizing
effect if it gets too high.

Exactly.

It's a bit too complicated for me to fully understand,
but, it's all summarized in this chart:
http://richardfalk.home.comcast.net/pool/HOCl.gif

Which is explained he
http://www.troublefreepool.com/threa...ater-Chemistry

End result?

The sanitizing goal is *not* a particular free chlorine level!
It's a particular free chlorine level that offsets whatever
your CYA level is.

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

A lot of this pool stuff is just handed down and a lot of it is
wrong.

I don't disagree.

Take, for example, the pool-store recommendations to reduce
phosphates to prevent algal growth.

Sure, algae need phosphates, but, free chlorine, in and of
itself, kills algae.

On the other hand, I did try to source industrial lanthanum
chloride salt crystals (active ingredient in Orenda PR-10000),
but, failed.

So, if anyone here can get a good price on industrial grade
lanthanum chloride, you can make a killing on the pool stores!

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

This isn't rocket science, you can experiment
and find out what happens.

Agreed.

For example, I plan on experimenting with one of the
rare-earth salts, to see if that can reduce phosphates
(even though chlorine above CYA is all that is needed
to prevent algae from growing) ...

Number . Symbol . Element ........... pKAP
.... 39 ......... Y ........ Yttrium ............ 24.76
.... 57 ......... La ....... Lanthanum ...... 26.15
.... 58 ......... Ce ...... Cerium ............. ? (probably 26.1)
.... 59 ......... Pr ....... Praseodymium . 26.06
.... 60 ......... Nd ...... Neodymium ..... 25.95
.... 61 ......... Pm ...... Promethium ..... ? (probably 25.97)
.... 62 ......... Sm ...... Samarium ........ 25.99
.... 63 ......... Eu ....... Europium ........ 25.75
.... 64 ......... Gd ...... Gadolinium ...... 25.39
.... 65 ......... Tb ...... Terbium ........... 25.07
.... 66 ......... Dy ...... Dysprosium ...... 25.15
.... 67 ......... Ho ...... Holmium .......... 25.57
.... 68 ......... Er ....... Erbium ............. 25.78
.... 69 ......... Tm ..... Thulium ........... 26.05
.... 70 ......... Yb ...... Ytterbium ......... 26.17
.... 71 ......... Lu ....... Lutetium .......... 25.39

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

I've never seen that table. What makes you think it's right?

J. O'Brien, J. Morris and J. Butler, €œEquilibria in Aqueous Solutions
of Chlorinated Isocyanurate€, Chapter 14 in A. Rubin, ed., Chemistry of
Water Supply, Treatment and Distribution, 1973 Symposium, (published 1974),
Ann Arbor Science, Ann Arbor, MI, pp. 333-358.


The following is an approximate formula you can use so long as your CYA ppm is at least 5 times your FC (the formula really falls apart terribly below a ratio of CYA/FC of 3).

(HOCl as ppm Cl2) = (FC as ppm Cl2) / ( 2.7*(ppm CYA) - 4.9*(FC as ppm Cl2) + 5 )

and if you are interested in the FC for a given HOCl (to construct the equivalent of Ben's table, for example), you can use the following which just solves for ppm FC from the above.

(FC as ppm Cl2) = ( 2.7*(ppm CYA) + 5 ) / ( 4.9 + 1/(ppm HOCl) )

The constants in the above formulas are for a pH of 7.5 (which is the only parameter that significantly affects these constants). With the spreadsheet I can easily calculate the constants for other pH, but remember that the above formulas are approximate. For example, with FC of 3 and CYA of 15 the formula gives HOCl as 0.098 when the correct answer is 0.095. That's not terrible (about an 3% error). However, with FC of 5 and CYA of 15 the formula gives HOCl as 0.239 while the correct answer is 0.199 (about an 20% error) which isn't as good.

A rough rule of thumb that applies at a pH of 7.5 is that the effective chlorine level is reduced by a factor about equal to the ppm of the CYA. So, a CYA of 30 ppm reduces the disinfecting chlorine (HOCl) level to about 1/30th of what it would be with no CYA.

"DannyD." wrote in
:

Subject: Actual price/gallon for 12% Hasa Pool Chlorine (for SMS
and the Silicon Valley) From: "DannyD."
Newsgroups: alt.home.repair,sci.electronics.repair

Zaky Waky wrote, on Wed, 25 Jun 2014 21:30:36 +0000:

Can you post some pics of the labels of the chlorine that you are
using?

Here is a picture of the chlorine "I" am using (Costco tablets & HASA
liquid):


Thanks.

On Wednesday, June 25, 2014 8:47:40 PM UTC-4, DannyD. wrote:
trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:



I've never seen that table.

What makes you think it's right?



While it stands to logic in that the more stabilizer you have, the more

free chlorine you need to maintain its effectiveness, I didn't make that

table up.



I didn't say you made it up. I said:

A - IDK where you found it, who made it up, what it's based on, if it's right.
Based on your link, it came from a guy called ChemGeek, who says this:

"ACKNOWLEDGMENT: The original chlorine/CYA chart was developed by Ben Powell and is shown here based mostly on experience plus some conversations with chemists. "

That doesn't sound like much of a basis for anything.


B - I find it hard to believe it's right, because if you look
at the water quality recommendation from pool standards organizations,
public health depts, etc, I've never seen the chart or anything
that says your high levels of chlorine are needed. They typically
say to maintain chlorine at 1 -3 and CYA at 30 - 60 is recommended. If you
really need to take chlorine to 8PPM when CYA is at 70, to sanitize
a pool, you sure would think they would say so, because it affects
millions of pools. It would be a health problem if many of those pools
need 8 ppm to sanitize but were only at 2 or 3.





The original Chlorine/CYA "Best Guess" chart was developed by Ben Powell.

Richard Falk had refined and expanded on that original to produce the

Chlorine/CYA Chart by Chem Geek as described he

http://www.troublefreepool.com/threa...rine-CYA-Chart



The point is that most people don't even realize that the free chlorine

that they need depends on the existing CYA level that they have!

I think the point is that you're one of the few with these very high
target levels for chlorine and that's why you go through hundreds of
pounds of trichlor, gallons of chlorine, need 4 floaters in a pool.
The four floaters boggles the mind, because it's like a tiger chasing
it's tail. You're putting large amounts of chlorine in because you
think you need it with higher CYA. But with 4 floaters, you're also adding
CYA at about 4X the rate the rest of us are, which in turn leads you to add
even more chlorine.

I'd suggest that you're reading something from one source that even
they say is based on personal observation. IDK what they were observing,
but following that as if it were gospel doesn't sound too wise to me,
especially when the stds orgainzations, health depts, who's job #1 is
to make sure pools are adequately sanitized say nothing of the sort.

Anyone else with a pool here targeting 5 to 9 PPM chlorine levels,
regardless of how much CYA they have? I keep mine at 1 -3 and have
no problems, no algae, clear water. I only have to shock it rarely
too.

Zaky Waky wrote, on Thu, 26 Jun 2014 07:36:37 +0000:

Thanks.

I made a slight typo on the HASA liquid chlorine; it's 12.5%, not 12.25%,
but the equation is otherwise correct (AFAIK).

trader_4 wrote, on Thu, 26 Jun 2014 05:31:48 -0700:

B - I find it hard to believe it's right, because if you look
at the water quality recommendation from pool standards organizations,
public health depts, etc, I've never seen the chart or anything
that says your high levels of chlorine are needed.

Hi trader_4,

I understand what you're saying, so, we need to look at this
closely, scientifically, and logically.

Both you and I can understand the *logic* of the CYA-to-chlorine
argument. It's why pool stores test CYA in the first place.

The higher the CYA, the less effective any one level of chlorine
is. We all know that, so, at least the "inherent" logic is
underlying the charts.

But is it science?

This technical bulletin lists a few scientific references:
http://www.aquaticspecialtyservices....hbulletin1.pdf

Namely, the following which, the bulletin says, conclude:
"cya inhibits chlorine's ability to kill bacteria".
a) American Journal of Public Health, October 1965, Anderson
b) Applied microbiology, May 1967, Fitzgerald

Yet, we are saying most "official" recommendations don't mention
the CYA level, right?

Here's an 'advisory', that says, essentially, the same thing:
http://www.accu-tab.com/Portals/0/pd...A_Advisory.pdf

So, maybe together, we can flesh this out, to understand why most
official chlorine recommendations don't seem to take into account
the CYA levels.

One potential "error" in our assumptions is that an *indoor* pool
probably doesn't have *any* CYA; so, any "official" recommendation
for chlorine levels in an indoor pool wouldn't be pertinent.

Another potential complicating factor is that, for outdoor pools,
the CYA levels might be "assumed". I don't know, as we'd have to
look at each official recommendation to be sure.

This post is getting long, so let me google for "official"
*outdoor* pool chlorine recommendations to see what I can dig
up to support or disprove the hypothesis.

trader_4 wrote, on Thu, 26 Jun 2014 05:31:48 -0700:

I'd suggest that you're reading something from one source that even
they say is based on personal observation. IDK what they were observing,
but following that as if it were gospel doesn't sound too wise to me,
especially when the stds orgainzations, health depts, who's job #1 is
to make sure pools are adequately sanitized say nothing of the sort.

Hi trader 4,

I'm all for the truth, and, I do understand your argument that we
should look to the health departments to see what their recommendations
are for *outdoor* uncovered pools.

But, I do refute the assumption that there is only one source for
the CYA levels hindering the effectiveness of the free chlorine.

I do agree that specific *chart* I referenced has few authors, but the
*science* behind the chart's assumptions is (apparently) sound.

The chart is an just a pragmatic attempt to make the known science
*applicable* to a pool owner. So, let's not concentrate too much on
the chart itself, and look to see if we can find official recommendations
for *outdoor* uncovered public pools.

Googling, for outdoor institutional pool chlorine recommendations,
I instantly find this "article", which discusses experiments
made at the outdoor Hall of Fame pool in Florida then at the University
of Hawaii outdoor competitive pool:
http://www.ppoa.org/pdfs/PrP_Cyanuri...0or%20Bomb.pdf

Again, that article (it's not a scientific paper but it lists about two
dozen scientific references) supports the theory that the CYA reduces
the sanitizing effectiveness of the chlorine by more than 1/3 at the
normally recommended levels of free chlorine (although it does discuss
the fact that bacteria do still die ... they mostly just die ten times
slower).

I'll keep looking for something "official" for *outdoor* pools...

On Thursday, June 26, 2014 10:02:56 AM UTC-4, DannyD. wrote:
trader_4 wrote, on Thu, 26 Jun 2014 05:31:48 -0700:



I'd suggest that you're reading something from one source that even

they say is based on personal observation. IDK what they were observing,

but following that as if it were gospel doesn't sound too wise to me,

especially when the stds orgainzations, health depts, who's job #1 is

to make sure pools are adequately sanitized say nothing of the sort.



Hi trader 4,



I'm all for the truth, and, I do understand your argument that we

should look to the health departments to see what their recommendations

are for *outdoor* uncovered pools.



But, I do refute the assumption that there is only one source for

the CYA levels hindering the effectiveness of the free chlorine.



I never said there is only one source for the CYA levels hindering
the effectiveness of chlorine. In fact, I acknowledged that it happens.





I do agree that specific *chart* I referenced has few authors, but the

*science* behind the chart's assumptions is (apparently) sound.


The sciene we agree on is that it has an effect. That says zippo
about the soundness of that chart, which the author even states is
apparently made on his personal observations, whatever that means.

My observation is that with CYA in a range of 30 to 70 or so, chlorine
levels of 1 - 3 have not caused any problems in my pool. And I don't
know of anyone except you that has these high chlorine targets, 4 floaters,
etc.






The chart is an just a pragmatic attempt to make the known science

*applicable* to a pool owner. So, let's not concentrate too much on

the chart itself, and look to see if we can find official recommendations

for *outdoor* uncovered public pools.



Googling, for outdoor institutional pool chlorine recommendations,

I instantly find this "article", which discusses experiments

made at the outdoor Hall of Fame pool in Florida then at the University

of Hawaii outdoor competitive pool:

http://www.ppoa.org/pdfs/PrP_Cyanuri...0or%20Bomb.pdf



Again, that article (it's not a scientific paper but it lists about two

dozen scientific references) supports the theory that the CYA reduces

the sanitizing effectiveness of the chlorine by more than 1/3 at the

normally recommended levels of free chlorine (although it does discuss

the fact that bacteria do still die ... they mostly just die ten times

slower).


Look at figure 1 of the above document and you can see that what you're
doing is a waste of time. Look at 40 PPM CYA. With a chlorine level of
1.5 you get an effectiveness of 660. Take the chlorine all the way up
to 4, and you get an effectiveness of 730. It effects it, but adding
4X the chlorine doesn't improve the sanitizing ability that much.

Then look at 60 PPM CYA. You can take the chlorine to 4, or even 8 as
you are doing, and what happens to the effectiveness? It's almost the same
as it is with the chlorine at 1.5, ie the additional chlorine isn't
doing anything to help you.

And you don't need super effective chlorine, you just need enough to do
the job. If X works, 2X or 6X isn't really going to work better, for routine
sanitation. And apparently with 60 CYA, 2 PPM chlorine is fine, except
apparently for the guy who came up with that chart.

Note that the above article you found, the author doesn't say that
you need 6, 8 whatever chlorine, like the chart you found. And as I've
pointed out, those levels are way beyond what every public health
authority I've seen recommends. If anything, it's more likely you're
going to find someone saying those levels are too high for the pool to
be used.

trader_4 wrote, on Thu, 26 Jun 2014 07:23:08 -0700:

And apparently with 60 CYA, 2 PPM chlorine is fine, except
apparently for the guy who came up with that chart.



Note that the above article you found, the author doesn't say that
you need 6, 8 whatever chlorine, like the chart you found. And as I've
pointed out, those levels are way beyond what every public health
authority I've seen recommends. If anything, it's more likely you're
going to find someone saying those levels are too high for the pool to
be used.

I'm all for the truth as numbers don't lie when they're done right.

What I'd like to find is a public health document for an outdoor
uncovered pool that shows they have "considered" the implications
of CYA in how it affects sanitizing at specific free chlorine
levels.

For example, this document is extensive, but doesn't cover the
topic all that well (they just assume a CYA level):
http://public.health.oregon.gov/Heal...ningbook09.pdf

trader_4 wrote, on Thu, 26 Jun 2014 07:23:08 -0700:

My observation is that with CYA in a range of 30 to 70 or so, chlorine
levels of 1 - 3 have not caused any problems in my pool. And I don't
know of anyone except you that has these high chlorine targets, 4 floaters,
etc.

Given your range of 30 to 70ppm CYA, notice this reference at 50ppm CYA
which is quoted in this previously noted PDF:
http://public.health.oregon.gov/Heal...ningbook09.pdf

"Crypto CT inactivation values are based on killing 99.9% of
Crypto. This level of Crypto inactivation *cannot be reached*
in the presence of 50 ppm chlorine stabilizer, even after 24
hours at 40 ppm free chlorine, pH 6.5, and a temperature of
77°F (25°C). €*€*
Extrapolation of these data suggest it would
take approximately 30 hours to kill 99.9% of Crypto in the
presence of 50 ppm or less cyanuric acid, 40 ppm free
chlorine, pH 6.5, and a temperature of 77°F (25°C) or higher.

Where the €*€* indicates this reference source:
Shields JM, Arrowood MJ, Hill VR, Beach MJ. The effect of cyanuric acid on the chlorine inactivation of Cryptosporidium parvum. J Water Health2008; 7(1): 109€“114.

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
================================================
================================================
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.
------------------------------------------------
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.
------------------------------------------------
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
------------------------------------------------

HOW CAN THE " THE STABILIZER WORKS OUT JUST RIGHT"? BE TRUE IN ANY SENSE? STABILIZER DOESNT "JUST WORK OUT" NO MATTER WHERE YOUR LOCATED!! SO THIS IS FALSE ON MORE THAN ONE POINT. "JUST WORKS OUT" HOW FUNNY !

--
For full context, visit https://www.homeownershub.com/mainte...nd-799652-.htm

AWESOME !!

--
For full context, visit https://www.homeownershub.com/mainte...nd-799652-.htm