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chem geek
09-13-2006, 02:22 PM
In trying to determine if the percent concentration of bleach on the Clorox bleach bottles and on their Material Safety Data Sheet (MSDS) forms was "Trade % Available Chlorine" (grams Cl2 equivalent per 100 ml) or "Weight % Sodium Hypochlorite" (grams NaOCl per 100 grams liquid), I sent TheCloroxCompany (that's their website name) an E-mail and I received the following response:



September 13, 2006

Mr. Richard Falk
(address and reference number withheld for posting on this forum)

Dear Mr. Falk,

Thank you for contacting us about Clorox Bleach - Regular Scent. We always appreciate hearing from our consumers.

For small wading pools that are emptied daily we recommend using 1/8 cup of Clorox Bleach - Regular Scent per 100 gallons of water.

For larger above ground or in ground pools we would recommend the following for initial dosages of the product.

5,000 gallons water - 3 cups bleach, 6,000 gallons - water 4 cups bleach,
8,000 gallons water - 5 cups bleach, 10,000 gallons water - 6 cups bleach,
15,000 gallons water - 10 cups bleach, 20,000 gallons water - 13 cups bleach,
25,000 gallons water - 17 cups bleach, 30,000 gallons water - 20 cups bleach,
35,000 gallons water - 23 cups bleach.

Note: 2 cups = 1 pint, 4 cups = 1 quart, 16 cups = 1 gallon.

One quart of Clorox Bleach - Regular Scent per 6,000 gallons of water will supply approximately 2 ppm (parts per million) available chlorine, but this may dissipate rather rapidly in new water depending on the general sanitation conditions of the pool. Repeat dosage as needed to obtain 0.6 to 1.0 ppm available chlorine. Use chlorine test strips to adjust to the desired
concentration.

In chlorinating a swimming pool, mix the required amount of Clorox Bleach - Regular Scent with 10 parts water and feed this solution through a chlorinator into the main water supply line to the pool. The feeding rate should be adjusted so the required quantity of this product will be added uniformly throughout the filling of the pool; or, if the water is circulated through a filter, the bleach should be added throughout one complete circulation. If the product cannot be fed into the main water supply line, mix 1/2 pint of the product with 5 gallons of water and scatter over a portion of the pool surface; repeat until the required amount of the product has been scattered over the entire surface of the pool.

Check chlorine level in pool water at least daily with a pool testing set and add this product as needed to maintain 0.6 to 1.0 ppm available chlorine. One pint of Clorox Bleach - Regular Scent per 6,000 gallons of water will supply approximately 1.0 ppm available chlorine. Frequency of application of this dosage will vary depending on number of people using the pool, weather conditions (sunlight exposure) and general cleanliness of the pool area. Chlorine level for acid-stabilized pools should be maintained at 1.0 to 1.5
ppm available chlorine.

The effectiveness of the chlorine is best when the pool water has a PH range of 7.2 to 7.6. The PH of the pool water should be checked daily using a pool PH testing set and adjustment as necessary.

The regular use of this product, in the above proportions, in the swimming pool usually prevents the growth of algae in the water; however, if algae growth is causing the pool water to look cloudy and uninviting, it may be corrected by doubling the initial dosage of the product for a few treatments. This additional product should be added to the pool in the evening after the pool is out of use so the excess chlorine will be dissipated before the pool is used again.

Avoid skin contact with undiluted product; is such contact occurs, rinse immediately with water. When added as recommended, this product has no deleterious effects on the eyes, nasal p***ages, or skin of people using the pool and will have no effect on swimming apparel.

Enclosed is also the most current MSDS Document we have on this product. We hope you find this information helpful. You can find all of our MSDS Sheets on-line at http://www.thecloroxcompany.com/products/msds/index.html.

I do apologize, this is the only information we have. I apologize, that I am unable to better ***ist you.

Again, thank you for contacting us.

Sincerely,


Natasha Stevens
Consumer Response Representative
Consumer Services


If you have additional questions or comments, please click here to respond to
this email.

So, this didn't answer my question as it is not clear exactly what the "Clorox Bleach - Regular Scent" concentration is, though the MSDS says it is 6.15%, but again I do not know if that is weight percent of NaOCl or if it is trade percent.

Their recommendation that 1 quart in 6000 gallons yields about 2 ppm available chlorine would be less than 5% trade and even less as weight percent of sodium hypochlorite. Also, they referred to "Clorox Bleach - Regular Scent", but the MSDS for "Clorox Scented Liquid Bleach" says there is less than 3% sodium hypochlorite so that can't be what she meant, while the MSDS for "Clorox Regular Bleach" says 6.15% sodium hypochlorite.

The recommendations in the E-mail are not good. Not only should one not use scented bleach, but they talk about an initial dose of 2 ppm and maintaining 0.6-1.0 ppm. Perhaps if one were not using any CYA, had no sunlight exposure on the pool, and had no child urinating in the pool then this level of chlorine would be OK, but clearly they don't know much about real-world disinfection in pools.

So, I am still left with the question of what exactly is the concentration of chlorine in bleach. For now, I am ***uming that what is printed on the bottle is "Trade %" so I've put into my spreadsheet an entry for 5.25% and 6.15% for cheap and regular bleaches and 7% for Ultra. I may go down and buy some fresh Clorox bleach (both Regular and Ultra if I can find it) as well as inexpensive no-brand bleach (if I can find it) at the store and do a dilution test, but if anyone has any reasonably accurate info on this, that would be helpful.

By the way, "Trade %" translates directly into ppm for the pool based on volume so Michael's Bleach calculator is exactly correct by simply using a volume dilution amount multiplied by this "Trade %" to determine ppm chlorine. We just have to determine when and where "Trade %" is used vs. "Weight % Sodium Hypochlorite".

Richard

waterbear
09-13-2006, 03:02 PM
I checked these amounts in mwsmith2's bleachcalc and got about 2 ppm (for example 1 quart or .25 gallons in 6000 gal water gave 2.2 ppm, 6 cups or .375 gal in 10000 gal water gave 2 ppm, and 1 oz per 100 gallons gave 2.1 ppm ) when using 5.25% which is the listed concentration on regular (not ultra) Clorox. It seems they are recommending a 2 ppm concentration based on their dosage which is in line with the newest minimum recommended dosing of many state Health departments and in line with Ben's best guess table for non stabilized pools. "Clorox Bleach-Regular Scent" is the name they give to their unscented bleach products (and they do state on their website that this is their only EPA registered bleach for sanitizing and disinfecting:
http://www.clorox.com/solutions_reg_bleach.php)
so this would be their 'unscented' bleach.
I agree that their recommdations for stabilized pools are not good nor are their recommendation for maintaining a .6 to 1 ppm residual.
It does seem that the 5.25% for their regular bleach as listed on the label is correct for our purposes based on bleachcalc and I would a s s u m e the 6% ultra bleach is also correct since that is the listed amount on the label of that product.
It is interesting that the MSDS for the regular bleach lists the concetration at 6.15% and the ultra bleach and the commercial Ultra germicadal bleach lists a range from 6% to 7.35%. Perhaps the higher concentrations are to compensate for loss of strength on shipping and storage so the consumer will have a product with at least 5.25% for the regular and 6% for the ultra products?
Hope this info is useful.

chem geek
09-13-2006, 03:15 PM
Thanks Evan. I also calculated 1 quart of 5.25% bleach in 6,000 gallons giving me 2.19 ppm chlorine (and using 7000 gallons would give 1.88 ppm chlorine).

This 5.25% vs. 6.0% (on a bottle of regular Clorox bleach I saw in the store a couple of days ago -- I'm pretty sure that wasn't Ultra, but I'll have to look again when I'm back in the store) vs. 6.15% on the MSDS for regular vs. 6-7.35% on the MSDS for Ultra is all confusing, to say the least. And it isn't explained by "bottle is Trade %, MSDS is Weight %" or anything like that.

I think that for practical purposes we can just ***ume that the percent listed on the bottle is Trade % and use the volume calculation in BleachCalc. I wanted to be more definitive about this, but even I recognize that I'm being way too picky about this. After I do some more checking at some stores to see what's really labeled on various bottles, I'll update my spreadsheet accordingly. It does seem that the 12.5% chlorinating liquid that I buy from a pool store (at $2.50/gallon) is indeed very close to 12.5 "Trade %". I don't mind paying a little more to carry fewer bottles (and I haven't found a convenient source of bleach that is that much cheaper -- i.e. less than $1.23 for 6.15% or $1.05 for 5.25%).

Thanks again for your help.

Richard

SeanB.
09-13-2006, 04:44 PM
Well, while the information wasn't accurate, it was nice of them to actually take the time to give a detailed response. I can't even imagine how many other companies nowadays would have just sent a form response or none at all.

Are you going to reply with "suggestions"? ;)

chem geek
09-13-2006, 08:16 PM
I did give some more info (suggestions, if you will) and asked to communicate with a technically knowledgeable person in manufacturing, but we'll see what comes of that. I agree with you that it was nice of them to at least respond, though I believe it is a standard response triggered by my use of the word "pool" which I had in my initial inquiry.

In the meantime, I did some quick research at some stores today and found that bottles of Clorox Regular bleach say 6.0% Sodium Hypochlorite and below that it says 5.7% available chlorine. So that strongly implies that the 6.0% is a weight % of sodium hypochlorite while the 5.7% is the weight % of available chlorine as defined in terms of the molecular weight of chlorine gas (which has, by definition, 100% available chlorine). This means that neither number is "Trade %" (grams available chlorine in chlorine gas molecular weight per 100 ml) which in this case would be about 6.2% and would be the number to be used in any simple volume scaling calculations (e.g. BleachCalc).

I also found chlorinating liquid that said 10.0% Sodium Hypochlorite which would imply a Trade % of about 11.0%. On the other hand, my recollection is that the chlorinating liquid I have been using says 12.5% and I believe that to be Trade %, but am not certain. Damn, this is SO confusing -- why did they even come up with this thing called "Trade %" anyway? I know that it makes volume-based calculations of ppm simpler, but it's one more way to accidentally mislabel a product!

I'll keep y'all posted (I can hear the yawns from here).

Richard

hamop78
09-13-2006, 10:01 PM
Richard,
I bought 4 cases (3 X 182 oz jug) of Clorox Ultra last weekend at Sam's --- the price worked out to 1.0333 cents per oz. I tested the product using the .1ml per 1L distilled water and got 6.8% using FAS-DPD w/25ml sample size. This reflects a higher percentage than they claim on their MSDS. I test every batch I buy. If I get a low batch --- Back it goes:mad: .

chem geek
09-13-2006, 11:09 PM
Richard,
I bought 4 cases (3 X 182 oz jug) of Clorox Ultra last weekend at Sam's --- the price worked out to 1.0333 cents per oz. I tested the product using the .1ml per 1L distilled water and got 6.8% using FAS-DPD w/25ml sample size. This reflects a higher percentage than they claim on their MSDS. I test every batch I buy. If I get a low batch --- Back it goes:mad: .
Just so you know, and now that we have all the terminology to get hopelessly confused, the 6.8% that you determined through the "volume" method is a "Trade %" since the FAS-DPD test measures ppm of chlorine as "available chlorine as ppm chlorine gas" and "Trade %" is "available chlorine as ppm chlorine gas per 100 ml".

The "Weight % Sodium Hypochlorite" is 6.5% and is within the range on the MSDS of 6-7.35% (which is a hell of a range!). You can convert from "Trade %" (i.e. your test measurement) to "Weight % Sodium Hypochlorite" by multiplying by 74.4422/70.906 = 1.05 and dividing by the specific gravity (density) of the liquid which is 1.1 for Clorox Ultra.

When comparing prices, you can factor the price per ounce by dividing by the "Trade %" (and multiplying by 100 for a reasonable scale) so in your case that is 15.2 while my source is 15.6 so is fairly close in price for what we are getting (though I carry less weight:D ).

Richard

waterbear
09-14-2006, 04:36 AM
In the meantime, I did some quick research at some stores today and found that bottles of Clorox Regular bleach say 6.0% Sodium Hypochlorite and below that it says 5.7% available chlorine.

Richard
Interesting....I just looked on the new jug of Regular Clorox in my laundry room and it, too, says 6% and I also looked at a jug of generic bleach from Ace Hardware and it says 5.25%. I also remember the older jugs of Regular chlorox used to say 5.25%. I wonder if Clorox has bumped up the strength of their bleach a bit so it 'whitens' better? The store I work at sells 'liquid chlorine' in both 10% (HTH brand gallons) and 12.5% (The carbouys we fill from our tank). The 12.5% is supposed to be around 14-16% when delivered, according to the company we get it from, to compensate for the loss of strenth on storage.
The plot seems to thicken the deeper we dig........

chem geek
09-14-2006, 03:52 PM
Yes, it does appear that Clorox increased their Regular concentration from 5.25% to 6.0% at some point in time so that 5.25% is now the generic brand concentration.

Additional inconsistencies abound. The chlorine I get from my pool store which comes in gallon plastic jugs labeled Sani-Clor and manufactured by Hasa, says on the bottle that it has 12.5% Sodium Hypochlorite as the active ingredient, but it also says that 3-1/4 quarts added to 10,000 gallons increases chlorine by 10 ppm. This latter calculation only makes sense if 12.5% is a Trade %. The $2.50/gallon price is just for the chlorine. The gallon jugs come 4 to a plastic case and there is a deposit per bottle ($0.50 I think) and case ($1.00 or $2.00 I think), but since I always just exchange one case with 4 bottles for another my effective cost is just the $2.50/gallon plus a tiny amount of interest I'm losing (by not investing) on the $4.00 total deposit.

On the other hand, I found Kem-Tek 10% chlorinating liquid that claims 10% Sodium Hypochlorite and it says that 11 ounces in 10,000 gallons yields 1 ppm which only makes sense if 10% is a Weight % of sodium hypochlorite and even then 12 ounces would be more accurate.

So what's the bottom line? It appears that the manufacturers are not consistent. Combine that with the loss of chlorine over time and this means you can really only know what you are getting by testing it, either through a straight dilution test or by testing your pool before and after a significant addition (waiting an hour). Picky, picky, picky...

Richard

medvampire
09-16-2006, 07:47 AM
We use to have to test each lot and shipment of chlorx coming in to the hospital by spec gravity. We used a refractometer and had a chart that would allow us to get a 6000 ppm dilution for sanitizing surfaces. We logged each test and the variances would astound you even with in lot test. The hospital where I work doesn’t test due to the HIV scare is winding down. Like Richard mentioned you may have to test each time.
Steve

fcfrey
09-18-2006, 10:33 PM
Since I am now injecting a bleach solution with a pump I test every batch I mix up. Today I over-shot on the pumping rate so I decided to mix a weaker concentration. I put one 182 oz bottle of Clorox with two 182 oz bottles of pool water to make what I would have thought to be a ~2% solution. When I tested it ---- it was 3.2% ---- repeated the FAS-DPD test and got the same thing???????:confused: ??????? I did not test the bleach before I mixed it.:mad:

My pool water was 7.3ppm but that's a long way from the 6% ?? bleach that it was mixed with.

chem geek
09-19-2006, 03:41 AM
Your 3.2% one-third diluted measurement doesn't make sense, even for Clorox Ultra. I don't know what to say. Perhaps try diluting it directly next time. And you are right that your pool water should have minimal effect on the final measurement since it is has so much lower chlorine level than the 6% bleach.

fcfrey
09-21-2006, 06:51 PM
I tested bleach and my injection solution again today and found the Clorox Ultra I bought from Sams is running about 7.2% by FAS-DPD test. What I can't figure is that a 1 to 3 (bleach to water) dilution is still testing at 2.4% solution for my injection pump. Does this compute??? (maybe it's this "new math";) )

chem geek
09-22-2006, 01:09 AM
I tested bleach and my injection solution again today and found the Clorox Ultra I bought from Sams is running about 7.2% by FAS-DPD test. What I can't figure is that a 1 to 3 (bleach to water) dilution is still testing at 2.4% solution for my injection pump. Does this compute??? (maybe it's this "new math";) )
Well 2.4% is a lot closer than the 3.2% you reported earlier. When you say "1 to 3" do you mean 1 volume of bleach in 3 volumes of water or do you mean 1 volume of bleach into 3 total volumes (i.e. 2 volumes of water)? You are right that starting with 7.2% and truly diluting 1 part plus 3 parts water (a 25% dilution) should yield 1.8% and not the 2.4% you are getting. On the other hand, if you were doing 1 part into 3 total (so 1 chlorine and 2 water), then this would be a one-third diultion which should get 2.4% which is exactly what you got. So either there is something really screwy or your 1 to 3 wasn't 1 part bleach and 3 parts water, but was 1 part bleach into 3 total parts (2 parts water).

Perhaps if you explain how you did the 1 to 3 dilution this might clear things up.

Richard

KurtV
09-22-2006, 02:27 PM
Aren't these home-brewed tests of chlorine strength hopelessly inaccurate? Aren't the errors inherent in diluting a sample to this level simply huge?

We tell people to dilute water samples by 3 or 4 to 1 so they can test higher chlorine levels with an OTO test but then warn them that the results are just ballpark. Now people are diluting chlorine samples by 20,000 to 1 (or so) and talking about tenths of a percent precision? I dunno...

chem geek
09-22-2006, 04:09 PM
Aren't these home-brewed tests of chlorine strength hopelessly inaccurate? Aren't the errors inherent in diluting a sample to this level simply huge?

We tell people to dilute water samples by 3 or 4 to 1 so they can test higher chlorine levels with an OTO test but then warn them that the results are just ballpark. Now people are diluting chlorine samples by 20,000 to 1 (or so) and talking about tenths of a percent precision? I dunno...
You are right that unless one uses a calibrated pipette, the errors will be quite large. However, having a large dilution ratio does not contribute to the error. An error in a ratio, which is what a 20,000 to 1 dilution is measuring, is only equal to the percentage or proportionate error in the numerator and denominator. If the "1" unit were one drop and this was only accurate to within half a drop, then this is a 50% error and is huge, but if the "1" unit were 1 ml and were measured in a calibrated pipette, then the error could be as low as 1%. The "20,000" large volume can be fairly easily measured to within 1%, again assuming one has an accurate large volume measuring tool (for liters or quarts, for example).

I'm not sure how fcfrey is doing the measurements, but you bring up a good point about accuracy. The easiest way to determine the rough accuracy of a measurement is to try and repeat the measurement and see if you get the same result, especially if you go on the low/high side for the small/large volume measurement and then repeat going on the high/low side.

Richard

fcfrey
09-22-2006, 06:27 PM
Richard/KurtV

When I diluted as in my last post, I dumped 1each – 182oz bottle of Clorox Ultra into a 6 gallon bucket. I then refilled the same bottle 3 times with pool water and combined these with the 7.2% bleach from the first step. To clarify --- that is 182 oz bleach and 546 oz water. This is a 1 to 3 solution ---- 4 parts total.

As for the dilution method for testing bleach I use a 1000 ml volumetric flask and a medical syringe used to perform the standard tuberculin “Tine” test. The syringe has a total capacity of 1 ml but is graduated in .01ml graduation intervals with major graduations at .1ml. Edit: The complete dilution method is only accurate to .1ml @20 deg C due to the accuracy of the volumetric flask ----- somehow I think that is "close enough".

Testing is done using the FAS-DPD method, using a 25ml sample size, again yielding accuracy within .2 ppm in a 10000 to 1 dilution.
If there is something wrong with the method please let me know. I have found the results to be repeatable with a 95% confidence level (in scientific terms [95 out of 100 tests]).

I am pretty anal with my testing methods.

KurtV
09-22-2006, 11:32 PM
Richard/FC,
Fair enough, I stand corrected.