Info from Clorox on using their bleach for pools

[chem geek]

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/prod...sds/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