Bleach vs Calcium Hypoclorite

fogeshan

Member
Feb 3, 2012
21
Johannesburg, SA
I'm trying to calculate if it's cheaper to buy household bleach (sodium hypochlorite) or granular calcium hypochlorite.

The bleach is only 3% concentration (I haven't been able to find liquid chlorine in my area).

I calculated that 200g of calcium hypochlorite is equivalent to about 375ml of bleach in terms of cost.
But i'm not sure which is more effective. Does anyone know how to work this out?
 

pabeader

LifeTime Supporter
TFP Guide
May 14, 2015
4,349
Cartersville Ga
Where are you located? We might be able to point out a supplier of higher concentration liquid.

As far as solid forms of chlorine, they work fine for the chlorination but they also add other stuff. In your case you would be adding calcium hardness.
 

domct203

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Jun 3, 2015
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CT
Where are you located? What is your pool surface/construction/type?

Cal-hypo will result in a buildup of calcium in the water, which will eventually make the pool difficult to manage due to the possibility of scaling. This will require water drains and refills to keep the calcium level manageable.
 

pabeader

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May 14, 2015
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Cartersville Ga
Since the calcium doesn't go away, over time you will have to drain some water off and replace it with calcium free water.
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,238
Greenville, SC
Where are you located? Generally in the US every grocery store has 8.25% bleach. Same with the ubiquitous Wal-Mart.

To answer your question, I believe 1lb of 65% Cal-Hypo is about the same as 1 gallon of 8.25% in terms of FC and is about $1 more. (Standard disclaimer Cal-Hypo increases CH eventually to a point of "too much")

edit: Holy Quadruple Post!
 

JoyfulNoise

TFP Expert
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May 23, 2015
15,265
Tucson, AZ
It depends on the % available chlorine. You want to compare the cost based on how much chlorine gas equivalent each provides as that is a direct comparison.

Typically speaking, the difference in price will be fairly minimal. The main benefit of cal hypo is that it packs a lot of chlorine into a small volume making it very easy to transport and carry around. The biggest drawback is it is very caustic and adds quite a bit of alkalinity to the water which will need to be controlled by acid additions. Also, for every 10ppm FC added by cal hypo, you roughly add about 6ppm to your CH. If your local water is soft, then the CH increase won't be a problem.

Bleach, by comparison is only slightly alkaline, affects pH very little and adds only a small amount of salt to the water. However, it is much bulkier to carry around and transport.


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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
10,237
Evans, Georgia
I'm not sure its even worth buying 3% bleach and lugging it home? Why bother when 8.25% is so readily available?

Try to avoid buying at Lowes and Home Depot, or any other place that stores their bleach outside in the garden center where its hot and sunny. That weakens bleach fast and you may end up buying 3% bleach but paying for 8%.

Walmart <insert shiver> does sell 10% liquid chlorine in their pool aisle. Check that out.

Yippee :flower:
 

Patrick_B

TFP Expert
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Jun 7, 2011
14,999
Midland TX
As Matt said, if you have soft water, its a good alternative. Even helpful if you need a Calcium source, cost aside. I don't think we say this often enough but its just fine in many cases.

Bleach is great, and the next best thing as an alternative to most sources of FC, but the cumbersome nature of getting it to the pool is undeniable.
 

randytsuch

LifeTime Supporter
Mar 29, 2008
256
Los Angeles, Ca
Costco is the most convenient for me
They sell 8.3% in three packs for $8.79 around me.

A little more expensive than HD when you compare compensating for % and fluid oz, but stored inside and we go to Costco about once a week anyway.
 

fogeshan

Member
Feb 3, 2012
21
Johannesburg, SA
I live in South Africa :)

I've been looking at bleach at my local grocery stores but they're all 3%.
I'm yet to look at our local equivalent to Walmart, as it's a bit of a drive, but looking at their website there are some brands I haven't seen before, so some might be stronger.

I've got a fibre glass pool.
I haven't had any issues with calcium deposits, but then it hardly ever needs refilling as we get a lot of rain.

According to the label, the calcium hypochlorite is 600g/1kg, so 60% then I guess.

I believe 1lb of 65% Cal-Hypo is about the same as 1 gallon of 8.25%
So, from that info, I get this:

200g of 60% calcium hypochlorite is about the same as 4.28l of 3% bleach, which works out to about 11x the price, so yeah, not worth it!

The biggest drawback is it is very caustic and adds quite a bit of alkalinity to the water which will need to be controlled by acid additions
Yeah, I tend to have to add acid quite often.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,265
Tucson, AZ
In you situation, I would use calcium hypochlorite. You're likely going to get enough rain dilution that your calcium levels will be decreasing more than increasing.

The more important question is this - do you have a good test kit for measuring your pool water? That will be much more important than what source of chlorine you'll be using.


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fogeshan

Member
Feb 3, 2012
21
Johannesburg, SA
The more important question is this - do you have a good test kit for measuring your pool water? That will be much more important than what source of chlorine you'll be using.
I do, but it only measures chlorine up to 3ppm, and no stabilizer or calcium :/
I need to inquire at my local pool shop, but I might have to import one.
 

JoyfulNoise

TFP Expert
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May 23, 2015
15,265
Tucson, AZ
I do, but it only measures chlorine up to 3ppm, and no stabilizer or calcium :/
I need to inquire at my local pool shop, but I might have to import one.
Yeah, 3ppm is not very useful if you don't know stabilizer levels. Does South Africa allow for the use of cyanuric acid? Typically countries that don't allow CYA to be used in commercial public pools also have limited sources of stabilized chlorine (dichlor and trichlor) on the retail side. If you've never used either of those then your water may not have any CYA in it. Having some CYA in the water is better than none at all and 30-40ppm would be a good level to start at. That would at least make the FC/CYA ratio ok for 3ppm FC.


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fogeshan

Member
Feb 3, 2012
21
Johannesburg, SA
Yup, it does. I've just added some actually. Based on the guidelines on the packaging, I estimate the the CYA to be around 30ppm now.

I've used trichlor in the past, but ended up having too much CYA in the water.
 

domct203

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Jun 3, 2015
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While reading up on chlorine and CYA, I came across this article which suggests a chlorine level of 7.5% of CYA: New Thinking: Chlorine/Cyanuric Acid In Balance - AQUA Magazine

So at 30ppm CYA, you get 2.25ppm FC. This is quite a bit lower than the 4-6ppm recommended by the Cl/CYA chart here. Thoughts?
Ben Powell is the founder of what we do here.

The 7.5 % is the minimum FC required to keep the pool sanitized, and is what the TFP minumum FC is based upon.

Our target range is recommeded as just that, a daily target that will allow for loss of FC throughout the day.
 

fogeshan

Member
Feb 3, 2012
21
Johannesburg, SA
Ben Powell is the founder of what we do here.
The 7.5 % is the minimum FC required to keep the pool sanitized, and is what the TFP minumum FC is based upon.
Our target range is recommeded as just that, a daily target that will allow for loss of FC throughout the day.
Ah ok, thanks for clearing that up
 

YippeeSkippy

Mod Squad
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Jan 17, 2012
10,237
Evans, Georgia
Ben Powell is the founder of what we do here.

The 7.5 % is the minimum FC required to keep the pool sanitized, and is what the TFP minumum FC is based upon.

Our target range is recommeded as just that, a daily target that will allow for loss of FC throughout the day.
And also cited in the article is ChemGeek, aka Richard Falk, the theoretical chemist who has many, many citations and threads here in the archives.
 

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