Making your own bleach/liquid chlorine?

avspin

Gold Supporter
Jun 3, 2015
61
Reno, NV
I have a general question about the difference between sodium hypochlorite vs calcium hypochlorite. Bleach is sodium hypochlorite and I was reading I can make my own bleach using a formula of 2 tablespoons of calcium hypochlorite (shock 70%) and 3 cups of water to make the concentrate. The add 8 drops of this concentrate to a gallon of water to create the standard 6% off the shelf bleach.

Putting the safety issue aside for the moment from the creation of toxic fumes. to make the concentrate.
Will this calcium hypochlorite bleach act the same as off the shelf bleach/liquid chlorine? Will this cause the ph to rise where the sodium will not?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,444
Tucson, AZ
The main problem is pH and stability. If you mix water and cal-hypo together, the pH of the resulting concentrate may not be high enough and you’ll wind up with a very unstable hypochlorite solution. It will degrade into salt, water and oxygen much faster than a commercially manufactured 6% bleach solution. The resulting “bleach” you do make will still have lots of calcium in it.
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,703
NW Ohio
Bleach is sodium hypochlorite, nothing but salt, chlorine, tiny bit of lye and water. Adding calcium hypochlorite to water just makes... wet calcium hypochlorite. It will have calcium, chlorine, and water.

Perhaps I'm completely missing something, but what is the point? You can use calcium hypochlorite directly in the pool.

Also that formula is WAY the heck off. A gallon of 6% will raise the FC of your pool by 3.1 ppm. An ounce (2 tablespoons) of 70% cal-hypo will raise the FC 0.2 ppm. Except you aren't even using that entire ounce, you are diluting it in 3 cups of water and then using 8 drops, which is what, a teaspoon? Let's be super generous and call it a tablespoon and you only diluted that 1/48th. So adding that to a gallon of water and then adding that gallon of water to your pool will raise your FC by 0.004 ppm. So instead of creating 6% bleach, you create 0.008% bleach, roughly. Dunno where you read that, but now you know just how bad the are at math.
 

avspin

Gold Supporter
Jun 3, 2015
61
Reno, NV
That is exactly what I thought with the math. I found three separate sites using that formula. Maybe the all copied from one.
My reason for asking is if you need to SLAM and in my city bleach 6% is $3 for less than a gallon it can add up to a couple of hundred. Looking for an alternate I contacted a couple janitorial supply's and I can get 12.5% bleach but at $7 a gallon. 10% liquid Chlorine is $4 at Walmart. So all over the place.
Just curious about the difference.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,444
Tucson, AZ
Typically speaking, 10% liquid chlorine (aka, pool shock) is usually the best bang for the buck. 12.5% is sometimes a good deal but usually you need to buy it in bulk (and it has the shortest shelf life).

SLAM’ing a pool is expensive both in terms of chlorine cost and testing reagents as well as personal time invested. That is why TFP stresses the importance of preventative maintenance, regular testing and consistent dosing of pool chemicals. I live in a similar part of the country you do and, in 6 years, I have had to SLAM my pool twice - both times it was a quick 48 hour fix, not a green swamp clean up. My neighbors that use pool services lose weeks of swimming time every season because, “Oh darn, your pool got the seasonal algae bloom again and, don’t ‘cha know this year is the worst year ever !! “ (said every year to the customer).

So, as the old saying goes, “An ounce of prevention is worth more than a pound of cure..”
 

avspin

Gold Supporter
Jun 3, 2015
61
Reno, NV
Fortunately have never needed to SLAM mine. I just opened last week and I have the usual green tint from not being turned on for 8 months. I just used about 10 gallons of bleach and bring everything else in line and all is good after a week. But in reading what some go through I was looking for alternatives.
 

sktn77a

Gold Supporter
May 16, 2010
1,148
Chapel Hill, NC
The problem with calcium hypochlorite is you are adding calcium to your pool. If you use enough to sanitize the pool, you calcium hardness will eventually increase to a value that is too high. Then you have to drain some of the water and start over.
 

johntniman

Silver Supporter
Apr 21, 2018
141
Las Vegas
That is exactly what I thought with the math. I found three separate sites using that formula. Maybe the all copied from one.
My reason for asking is if you need to SLAM and in my city bleach 6% is $3 for less than a gallon it can add up to a couple of hundred. Looking for an alternate I contacted a couple janitorial supply's and I can get 12.5% bleach but at $7 a gallon. 10% liquid Chlorine is $4 at Walmart. So all over the place.
Just curious about the difference.
Have you looked at hardware stores? At least in Vegas, both Home Depot and Lowes carry 10%. Lowes is 10%, 2 gal for just shy of $7. Being in Reno, you probably have to worry less about it being stored outside.

[Edit:] Maybe HD doesn't carry it up there. It looked like it did on the site.
 
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avspin

Gold Supporter
Jun 3, 2015
61
Reno, NV
Both my Home Depot and Lowes only have Clorox 6%, 121oz. and it's more than 1 gal Walmart liquid chlorine at 10%. They use to have their own brand but not at the moment.
 

Geebot

Well-known member
Aug 19, 2013
841
An ounce (2 tablespoons) of 70% cal-hypo will raise the FC 0.2 ppm. Except you aren't even using that entire ounce, you are diluting it in 3 cups of water and then using 8 drops, which is what, a teaspoon? Let's be super generous and call it a tablespoon and you only diluted that 1/48th. So adding that to a gallon of water and then adding that gallon of water to your pool will raise your FC by 0.004 ppm. So instead of creating 6% bleach, you create 0.008% bleach, roughly. Dunno where you read that, but now you know just how bad the are at math.
What? You've never heard of homeopathic pool chemistry?
 
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Reactions: Donldson

mariane

LifeTime Supporter
May 8, 2012
621
Southeast Michigan
Putting your numbers into Chlorine Price Per Ounce Calculator :
Lowes 2 jugs of 10% @ $7 works out to $.273 which shows fair price.
Your city bleach 6% (121 oz) @ $3 = $.413 - horrible.
Janitorial's supply 12.5% @ $7 = $.438 - horrible.
Walmart 10% @ $4 = $.312 - poor
Looks like Lowe's would be the best option since it's not a bad price.
This liquid chlorine calculator is great to use. It was down for a while, but now back up. :cool: