Isn't 10% "liquid chlorine" cheaper than bleach?

[kearpaul]

Hello,

Was hoping this esteemed forum could chime in on this. Kinda a math problem.

Around here, you get 3 quarts of 5.25% bleach for $1.30. Liquid chlorine (10% sodium hypo) is two gallons for $6. If I'm doing my math right, the bleach is 1.3 cents per oz [$1.30/3/32 ounces in a quart]. BUT you have to make the strength equal by multiplying by [10/5.25]. We then arrive at 2.6 cents per ounce for "10% bleach".

For the 10% LC, it comes to 2.3 cents per ounce. [$6/2/128 ounces per gallon].

So, LC is slightly cheaper for me. And I have fewer bottles to throw away.

Am I getting tangled up over nothing?

Cheers from the underchlorinated Sierra Foothills,
Paul

_ _ _ _ _
Someone told me my work was like the cotton in the aspirin bottle. You didn't know what it was there for; you just knew it aggravated the hell out of you.
Former Giants broadcaster Lon Simmons

[CarlD]

No, sometimes it DOES work out that way. Say it's actually 10.5% vs 5.25--then if the LC was less than double the price of the 5.25% bleach, it's cheaper.

Suppose that 5.25% is $2/gallon. A carboy of 5 gallons of 10.5% is the equivalent of 10 gallons--therefore ANYTHING less than $20 for the carboy is a bargain...given those numbers.

I find the carboys convenient (I recycle bleach bottles to refill) but I'm aware that at 12.5-14% the chlorine breaks down fast. I'll fill empty bleach bottles with half-water then half LC to get it down to the 6-7% range...Lately it's STILL cheaper than bleach.

[JohnT]

You might want to double check your bleach. I've never seen 5.25% bleach in a 3 quart jug. It usually comes in gallons and the 3 quart is the ultra or 6% bleach. The Walmart bleach is 3/4 gallon of 6% for $1.28 most places. The bigger jug is even cheaper.

If you throw away the water and lye in the jug "theoretically" you get:

A 3 quart jug of ultra bleach contains 5.76oz sodium hypochlorite
A 1 gallon jug of 10% shock contains 12.8oz sodium hypochlorite


The ultra bleach is 22.2 cents per ounce for the NaOCl
The 10% shock is 23.43 cents per ounce for the NaOCl

The shock gives you fewer bottles for just a little more than the ultra bleach, but the higher concentration is more subject to losing strength from heat and time. My guess is the shock will spend more time sitting in the store than the bleach, especially later in the summer. The bigger jug of Walmart bleach is a better deal than the 3qt, but I don't remember the details.

[waterbear]

It really depends on where you are. In my area a gallon of 5.25% is $1.49 (best price I have seen) and 3 quarts of 6% is about $2.29. 2.5 gallon carboys of 10.5% by weight (the 12.5% stuff by volume of chlorine) goes for about $4 on a refill. There is a one time fee for the carboy at most places that ranges from $4 to $6. It's a no brainer!

[kearpaul]

JohnT, you caught me. I checked the bleach and it is 6%, not 5.25% as I said. Maxima mea culpa. I like the way you boiled down the equation to remove water and lye.

Now, Carl and Evan, if you would please tell me more about carboys. Warning: newbie questions dead ahead. What kind of places sell carboys? It contains 2.5 gallons of the 'hard stuff' in a returnable container? Is it reasonably safe to store a carboy in a hot garage? The way my pool is ripping through chlorine, it sounds these are the way to go.

Cheers from the Sierra Foothills,
Paul

_ _ _ _ _
We may not pay Satan reverence, for that would be indiscreet, but we can at least respect his talents.
Mark Twain

[AnnaK]

For me, the 5 gal carboy of the higher concentration bleach is by far the most economical. The intial deposit is $6 and refills are $3/gal. I keep the carboy in the garage and transfer the bleach to an old Clorox bottle with a syphon.

Not only do I save a little bit of money but I cannot justify the large number of plastic bottles I'd be going through if I bought bleach by the gallon. It's a pretty serious waste disposal issue out here in the contry.

I buy the carboy refills at the pool store. Pool stores aren't all bad :)

Anna

[CarlD]

Carboys are blue containers...some are square, some are round--but most stores use the square ones and you can return the "deposit" carboys to any store that uses them. Some stores have 2.5 gallons, but here in NJ they are mostly 5 gallons.

Better than a syphon: A lot of the pool stores sell a spigot for the carboys for about $4. that replaces the cap--like an old-fashioned beer-barrel tap.

You can test the strength yourself:
1) Use a 1 ml eyedropper (most drug stores have them, or a child's used-up cold medicine eye-dropper).
2)Add 1 ml to 10 liters of tap water
3) that's5x 2 liter soda bottles and you are diluting it to a concentration of 1:10,000.
4) and measure EXACTLY as if you were testing your pool.
5) Whatever you read (say, 5.75ppm or 13.5ppm) is the REAL concentration of the bleach/liquid chlorine.


You MAY want to test your tap water first for chlorine and adjust accordingly.

[Spensar]

What kind of places sell carboys?

Aside from pool stores you can also try industrial cleaning supplies (my source).

[AnnaK]

The carboys here in Pennsylvania are yellow. They look like jerry cans and have a red lid covering the fill hole on top of the canister. I like the spigot idea but can't figure how that would work on these types of carboys. The syphonig can be messy though I've gotten prety darn good at knowing just when to turn the suction off to fill the bottle but not spill over.

The things we learn with the care and feeding of a swimming pool!

[kearpaul]

Thanks everyone. Very helpful.

Best,
Paul

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I'm a peripheral visionary. I can see into the future -- just way off to the side.
Steven Wright