Cost of raising FC by 1 ppm

[AnnaK]

I got interested in the economy of the different bleach solutions available and thought I'd share my findings with you.

Cost of bottled bleach:
Pool store carboy @ 12.5% = $0.0218/oz
Sam's Club, Clorox Ultra @ 6% = $0.023/oz
Sam's Club, Clorox regular @ 5.25% = $0.019/oz

Original Bleach Calculator Formula:
(1,000,000/PV) * C * UB = FC ppm Added

Formula reworked for Units of Bleach needed to increase FC by 1 ppm:
FC * 1/C * PV/1E6 = UB

My pool volume is 12,000 gallons. Hence:

1 * 1/0.1 * 0.012 = 0.12 gal = 15 oz @ 10% Pool store ----> $0.33
1 * 1/0.0525 * 0.012 = 0.23 gal = 29 oz @ 5.25% Regular ---->$0.55
1 * 1/0.06 * 0.012 = 0.2 gal = 25 oz @ 6% Ultra ----> $0.58

The pool store chlorine is said to be at 12.5%. I'm using a 10% functional concentration in my calculation because chlorine degrades with time and storage conditions. I have not tested the concentration to get a real number because the dilution factor using my Taylor reagents makes my head explode.

I use a 4 cup plastic measuring cup to add bleach. You may already know this but Google has a neat units converter. You input "0.12 gal = ? oz" and it returns 15 oz. Or you say "15 oz = ? cups" and it tells you 1.875 cups.

I should be cleaning house in preparation for weekend guests but this was more fun. Unless I got the math wrong, in which case I'll be really, really embarrassed.

[cleancloths]

Well your math may be correct, but I think you can find much cheaper bleach. I routinely buy 5.25% bleach at the supermarket for $1.49/gallon which comes out to $0.01164 per ounce. I stock up when it goes on sale several times a year for $1 a bottle which is only $0.0078 per ounce!

[AnnaK]

That's a good deal, just about the same as the pool store chlorine. When you buy it at the regular price it comes out to $0.34 per 1 ppm FC.

[heymom1]

Well your math may be correct, but I think you can find much cheaper bleach. I routinely buy 5.25% bleach at the supermarket for $1.49/gallon which comes out to $0.01164 per ounce. I stock up when it goes on sale several times a year for $1 a bottle which is only $0.0078 per ounce!

Do you have a basement? Where do you store this bleach when you buy it ahead? Wish I could, but there's no place to put a large quantity.

6% bleach here runs about the same price. I just can't store very much at a time.

[Jeffski]

So why are we all buying bleach when the pool store chlorine is cheaper?

[KurtV]

So why are we all buying bleach when the pool store chlorine is cheaper?

1. It's not available in all locales.
2. Many people don't have a pool store located conveniently close while almost everyone has easy access to a grocery store and visits one at least weekly.
3. Relatedly, you don't have to make another trip to another store to get bleach; you can just pick it up while you're at the grocery or Wal-Mart or wherever.
3. The 12.5% stuff, because most people won't use a whole container at once, whether it's stored in carboys or jugs, requires more handling with a greater potential for spills and splashes that will damage clothing and other things.
4. The stronger stuff degrades more quickly.

[cleancloths]

Store it in the garage or the basement of my store. I don't like stuff over 10% as it degrades very quickly. Further, they require that you give them a deposit on the containers and it is just a pain. When bleach is on sale at the market it is the cheapest form to buy.