10% chlorine what is other 90%?

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
Henry_R
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10% chlorine what is other 90%?

Postby Henry_R » Wed 24 Aug, 2011 19:44

Hi all, I'm wondering what the other 90% of a 10% liquid chlorine bottle is? Bottle says "10% Sodium Hypochlorite, 90% inert ingredients".

Someone from a pool store said the stuff has stabilizer in it, but the bottles don't agree. I know some of the inert stuff is sodium salts since it's sodium hypochlorite, but does that make up the entire 90% of the "inert ingredients"?


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chem geek
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10% chlorine what is other 90%?

Postby chem geek » Wed 24 Aug, 2011 22:31

Chlorinating and bleach have the same ingredients, just at different concentrations. 10% sodium hypochlorite will have 7.8% sodium chloride salt because the product is made by adding chlorine gas generated from electrolysis to a solution of sodium hydroxide (lye) as follows:

Cl2(g) + 2NaOH ---> NaOCl + NaCl + H2O
Chlorine Gas + Sodium Hydroxide ---> Sodium Hypochlorite + Sodium Chloride + Water

The different percentages are due to the different molecular weights since these are weight percentages.

In addition to the above, there is a small amount of excess lye (sodium hydroxide) in the product to keep the pH a little higher than it would otherwise be in order to provide greater stability (i.e. shelf-life). 6% regular unscented Clorox bleach has the lowest excess lye at around 0.063% while chlorinating liquid usually has around 0.25% though some inferior brands may have more.

Clorox bleach also has a small amount of sodium polyacrylate which is used as a metal sequestrant to prevent yellowing of clothes from iron or manganese that may be in the water.

The rest is water.

There is no Cyanuric Acid / stabilizer / conditioner in bleach or chlorinating liquid. In fact, the main reason for using sodium hypochlorite is to add chlorine while avoiding the addition of either CYA or calcium. The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

Some pool stores may give you a line about chlorinating liquid or bleach adding salt to the pool, but what they neglect to tell you is that ALL sources of chlorine increase salt levels over time because chlorine becomes chloride when it gets used up. For every 10 ppm FC added by ANY source of chlorine, it results in 8 ppm salt. It is true, however, that chlorinating liquid, bleach, and lithium hypochlorite add additional salt to the pool for reasons I gave earlier. For every 10 ppm FC from these sources, the net result is around 17 ppm salt. Cal-Hypo is in between at around 10-12 ppm salt. Salt, however, is far more innocuous than CH and especially CYA.
Henry_R
Swimming Pool Pro
Swimming Pool Pro
Posts: 126
Joined: Fri 20 Mar, 2009 21:41
My Pool: HOA Community Swimming pool built approx. 1971.
In-Ground, Plaster 34x18 3.5-6' deep, Sta-rite P2R A5D-120L pump, A.O. Smith centurion 1HP (uprated 1.25HP) motor,Hayward S244S filter(new 2011), Rainbow Lifegard Chlorine/Bomine feeder; new replastered June 2010
Location: Houston, Texas USA

10% chlorine what is other 90%?

Postby Henry_R » Thu 25 Aug, 2011 07:59

chem geek wrote:Chlorinating and bleach have the same ingredients, just at different concentrations. 10% sodium hypochlorite will have 7.8% sodium chloride salt because the product is made by adding chlorine gas generated from electrolysis to a solution of sodium hydroxide (lye) as follows:

Cl2(g) + 2NaOH ---> NaOCl + NaCl + H2O
Chlorine Gas + Sodium Hydroxide ---> Sodium Hypochlorite + Sodium Chloride + Water

The different percentages are due to the different molecular weights since these are weight percentages.

In addition to the above, there is a small amount of excess lye (sodium hydroxide) in the product to keep the pH a little higher than it would otherwise be in order to provide greater stability (i.e. shelf-life). 6% regular unscented Clorox bleach has the lowest excess lye at around 0.063% while chlorinating liquid usually has around 0.25% though some inferior brands may have more.

Clorox bleach also has a small amount of sodium polyacrylate which is used as a metal sequestrant to prevent yellowing of clothes from iron or manganese that may be in the water.

The rest is water.

There is no Cyanuric Acid / stabilizer / conditioner in bleach or chlorinating liquid. In fact, the main reason for using sodium hypochlorite is to add chlorine while avoiding the addition of either CYA or calcium. The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

Some pool stores may give you a line about chlorinating liquid or bleach adding salt to the pool, but what they neglect to tell you is that ALL sources of chlorine increase salt levels over time because chlorine becomes chloride when it gets used up. For every 10 ppm FC added by ANY source of chlorine, it results in 8 ppm salt. It is true, however, that chlorinating liquid, bleach, and lithium hypochlorite add additional salt to the pool for reasons I gave earlier. For every 10 ppm FC from these sources, the net result is around 17 ppm salt. Cal-Hypo is in between at around 10-12 ppm salt. Salt, however, is far more innocuous than CH and especially CYA.
Wow, that's a great analysis of chlorine liquid. So is it safe to believe that the 90% inert ingredient is H2O; water? I do wish the companies selling the stuff would state as much on the labels if it is.

Interesting that clorox has that metal sequestrant. Is there sufficient quantity to be of use in a pool? We have very hard tap water and galvanized water pipes which are >40 years old. These condos were built about 1971 as apartments. We might have trace amounts of metals (chromium? whatever they used for galvanization of steel water pipes in the 1960s, early-70s) in our pool water when we fill it, but it's not a problem so far as I can detect. But perhaps it would be beneficial to use clorox every so often just the same.
Money talks!? All it ever says to me is "goodbye!".
chem geek
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10% chlorine what is other 90%?

Postby chem geek » Thu 25 Aug, 2011 12:54

10% Sodium Hypochlorite (chlorine)
7.8% Sodium Chloride (salt)
about 0.2% Sodium Hydroxide (lye)
82% water

The amount of sodium polyacrylate in Clorox Bleach is too small to consider that a metal sequestrant for pools since it gets much more diluted than when used for laundry.

When you buy a product that is a liquid and it says it is mostly inert ingredients, then that is pretty much always water. If it were some other kind of solvent, then that would be listed.

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