# Treating Water with Calcium Hypochlorite



## swjohnsey

I have treated water in a variety of ways, Katadin Pocket Filter, bleach, iodine tablets. For years I didn't know bleach had a shelf life. Recently I came across calcium hypochlorite as a method for treating drinking water. The is commonly used as pool shock for treating swimming pools. It is granular and you can by it in one pound bags at places like Lowes. It stores indefinately and is cheap. I think I paid about $4/lb. The complication is that it comes in a variety of strength. The online source I found for instruction was using 78% calcium hypochlorite but the best I could find was 56.44%. 

After making a mess in the kitchen and pissin' off my wife I came up with something that works using test strips for swimming pool and spas. EPA maximum for chlorine in drinking water is 4 ppm max and 0.2 ppm min. 

Take level 1/2 teaspoon of the 56.44% calcium hypochlorite (about 3 grams) and mix it into 8 ounces of water. This 8 ounces of solution will treat about 60 gallons of water. Take 1/2 teaspoon of the solution you just mixed and add it to a gallon of water to be treated. Just like bleach or any other chlorine source you need to let it sit for 30 minutes, longer if the water is very cold. Use double the solution if the water is nasty. The mixed solution has a limited useful life, maybe a month, so don't mix a bunch. 

If you want to be precise you can buy a pool test kit to test for residual chlorine after treating your water. Ideally you want the residual chlorine low at less than 1 ppm but 4 or even higher won't hurt you.

There are some organisms that chlorine doesn't do a real good job of killin', among them cryptosporidium a giardia.


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## 8thDayStranger

So just out of curiosity, do you think if someone had a 55 gal drum of water, panicked, and treated it for some reason and never used it, they would be able to retreat it if needed and it be ok? Do you know if the stuff just breaks down and disappears or could it leave something to taint the water?


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## swjohnsey

Chlorine disipates with time which is why cities test their water at the end of the distribution system. Just retreat it.

Interestingly enough, when I tested the water that came out of my tap there was no residual chlorine.


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## OldCootHillbilly

Not ta hijack yall's thread, but here be a neat little item what I use fer that same purpose, might help ya out some.

http://www.preparedsociety.com/forum/f20/pvc-water-purification-kit-17378/

Ifin ya watch at the end a the season, ya can find calhypo on clearence. I picked up several bags what was 50% off cause it were outa season. Good time ta stock up.


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## hiwall

Just a caution with dry calcium hypochlorite - - do NOT allow to come into contact with any oil (petroleum product or organic). It is an extreme fire hazard. Never store them anywhere near each other.


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## IlliniWarrior

one of the main reasons for the required 70%+ concentrate is to avoid all the unwanted additives that come with the 50% retail store pool shock ....

for the correct pool shock of 70%+ you need Ultra or Super Pool Shock .... sold thru commercial pool supply stores or available online ..... 

already mentioned ... calcium hypochlorite is really bad azz stuff ..... in gaseous form it's highly corrosive and lethal in a confined space ..... 

do not store in a metal container because of corrosion and a glass container due to breakage/spillage .... use a locking lid ALL poly container that is well marked with content .....


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## swjohnsey

Calcium hypochlorite is nasty. Also be careful around water. Always add the calcium hypochlorite to water. If you add water to calcium hypochlorite you will get a violent reaction.

I'm gonna look for some better (purer) stuff. I am stuck in the sticks, no pool supply place only Walmart and Lowes. When you mix the initial solution the calcium hypochlorite disolves and the inert ingredients are left on the bottom of the container. If you poor it off carefully you will get rid of most of it. I fiddled the formula slighty to get a little less residual chlorine and used 10 ounces of water instead of 8.


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## BillS

Calcium hypochlorite is an acid. When it reacts to something it gives off chlorine gas. It's effects are temporary.


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## IlliniWarrior

swjohnsey said:


> Calcium hypochlorite is nasty. Also be careful around water. Always add the calcium hypochlorite to water. If you add water to calcium hypochlorite you will get a violent reaction.
> 
> I'm gonna look for some better (purer) stuff. I am stuck in the sticks, no pool supply place only Walmart and Lowes. When you mix the initial solution the calcium hypochlorite disolves and the inert ingredients are left on the bottom of the container. If you poor it off carefully you will get rid of most of it. I fiddled the formula slighty to get a little less residual chlorine and used 10 ounces of water instead of 8.


there's several pool supply wholesalers online that have great pricing and free delivery ...... they usually beat the regular pool supply stores on pricing ....


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## cowboyhermit

There is stuff that is used to shock treat wells, you can be certain it doesn't have any chemicals added to it. Most plumbers in rural areas seem to carry it, or well drillers.


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## swjohnsey

Found some better pool shock 73% from Ace Hardware about $5/pound. Didn't notice much difference between the 57% stuff in the amount of residue or even the strength.

I wanted to get the initial chlorine level under 4ppm since this is the EPA guideline. After a bunch of fiddling to get something that was useable in the field with crude measureing equipment here is what I came up with. To 6 ounces water add 1/2 tsp of the calcium hypochlorite. To treat a gallon of water add 1/2 tsp of this water/calcium hypochlorite mixture. For anyone who plans to treat water using this method I recommend you play with this before it is for real. Get you some pool test strips. Some of the direction I have found online are wildly off. I found it easiest to adjust the strength by altering the amount of water used to make the initial mixture. Starting with 4 oz will get you in the ballpark and you can slowly add water to you get the level down to the level of chlorine you can tollerate. Any risidual chlorine after 30 minutes is what you are looking for.


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## DKRinAK

swjohnsey said:


> Found some better pool shock 73% from Ace Hardware about $5/pound. Didn't notice much difference between the 57% stuff in the amount of residue or even the strength.
> 
> I wanted to get the initial chlorine level under 4ppm since this is the EPA guideline. After a bunch of fiddling to get something that was useable in the field with crude measureing equipment here is what I came up with. To 6 ounces water add 1/2 tsp of the calcium hypochlorite. To treat a gallon of water add 1/2 tsp of this water/calcium hypochlorite mixture. For anyone who plans to treat water using this method I recommend you play with this before it is for real. Get you some pool test strips. Some of the direction I have found online are wildly off. I found it easiest to adjust the strength by altering the amount of water used to make the initial mixture. Starting with 4 oz will get you in the ballpark and you can slowly add water to you get the level down to the level of chlorine you can tollerate. Any risidual chlorine after 30 minutes is what you are looking for.


Thank you!

The EPA guidelines for 'home use' are both potentially confusing and require measuring devices calibrated in mL or oz.

*Your method uses a single volume measure and one most folks have on hand. Brilliant!*

I will also echo the warnings on this stuff, it will BURN. Don't ask how I know, it's a long boring story.


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## JayJay

I found a really easy mixing recipe to remember from a seasoned prepper website:
1 tsp. of ch to 2 liter of water for solution
2 tsp. of solution to 1 gallon of water to treat.

1 to 2, then 2 to one!!
And keep the tsp., 1 gallon jug labeled, (1) 2 liter jug labeled, and directions in a bag.


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## swjohnsey

I'm gonna try that. Does it say what percentage of calcium hypochlorite to use?


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## SlobberToofTigger

The problem with set ratios is that they do not deliver the correct amount of chlorine when you are using dirty water. They are better than nothing, but using a test kit on your finished product like swjohnsey is doing is the only way to know if you have the correct amount of chlorine in your water. You know this because you are testing for residual chlorine after it has done its work not the initial amount of chlorine you just added.


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## Attila

Municipal water systems are required by law to carry a chlorine ppm of .2, which means the closer you are to the water treatment plant, the higher the ppm of your municipally supplied water. Chlorine breaks down quickly as temperature of the water rises. When chlorine breaks down it from hydrochloric acid, however, the HLC is pretty weak.


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## swjohnsey

Very true. Also temperature is a factor. Very cold water also takes more. Always a good idea to try and filter out the floaties before treating.

I tried the formula using the same technique I was using with mine. Came out very good, something under 4 ppm. This is what I was looking for when I set out, a simple formula using crude measuring equipment I would likely have handy. I think I like this one better.

I'm gonna use this stuff on some of the local creek water (nasty even by my standards) to see how much it takes to get it fit to drink.


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## hiwall

If you aerate the water it removes alot of the chlorine.


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## prepperware

This may be the time to interject this tidbit... making your own chlorine solution with just salt and water. 

You may have seen the portable water purification system they sell that takes salt and water and produces chlorine using a electrical charge that converts the solution to chlorine? You can do this at home too with a DC power source. With this system you will never be out of chlorine as long as you have salt and a power source... I've done this at home and it is amazing process.. I put two electrodes from a motorcycle battery in a glass with salt water in it... after a minute or so you can smell the chlorine.. I did not experiment how long, vs how much salt/water etc.. but it is a good process to know if you have no other source for chlorine.. Those of you more savy in chemistry may know if you must only use salt that does not have iodine...


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## JayJay

~~~With this system you will never be out of chlorine as long as you have salt and a power source... ~~~

With 4 bags of ch, and each bag servicing 10,000 gallons, I think I am set for the duration of my life.
That's 40,000 gallons @ 2 gallons a day= 20,000 days or 50 years:congrat:

And, I'm still adding to my supply for maybe helping others??


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## JayJay

swjohnsey said:


> I'm gonna use this stuff on some of the local creek water (nasty even by my standards) to see how much it takes to get it fit to drink.


I actually am gonna treat water after a rain to see how that works.
I will let you know.
Filter with coffee filter, boil, add CH, then use the Berkey.


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## IlliniWarrior

swjohnsey;256337 said:


> Found some better pool shock 73% from Ace Hardware about $5/pound. Didn't notice much difference between the 57% stuff in the amount of residue or even the strength.
> 
> I wanted to get the initial chlorine level under 4ppm since this is the EPA guideline. After a bunch of fiddling to get something that was useable in the field with crude measureing equipment here is what I came up with. To 6 ounces water add 1/2 tsp of the calcium hypochlorite. To treat a gallon of water add 1/2 tsp of this water/calcium hypochlorite mixture. For anyone who plans to treat water using this method I recommend you play with this before it is for real. Get you some pool test strips. Some of the direction I have found online are wildly off. I found it easiest to adjust the strength by altering the amount of water used to make the initial mixture. Starting with 4 oz will get you in the ballpark and you can slowly add water to you get the level down to the level of chlorine you can tollerate. Any risidual chlorine after 30 minutes is what you are looking for.


it's that 15 - 20% odd ingredients you don't want involved in your potable water .... just use the greatest concentrate you can find over 70% and be on the safe side


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## LincTex

swjohnsey said:


> Take level 1/2 teaspoon of the 56.44% calcium hypochlorite (about 3 grams) and mix it into 8 ounces of water. This 8 ounces of solution will treat about 60 gallons of water.


So basically about 1/2 tsp per 55 gallon drum?


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## swjohnsey

Sounds 'bout right. Here is the deal. Chlorine dissapates with time. If you treat 55 gallons it will be good to drink today or even for a week. It might not be good to drink in a couple of weeks because the chlorine will be gone and bad things can grow back.

On the other stuff in pool shock. When you mix it with water you will get some solid stuff that does not disolve. With a little time it will settle out and you can pour off the clear liquid so you won't have it contaminate your water. It is pretty insignificant even if you don't get rid of it.


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## LincTex

swjohnsey said:


> It might not be good to drink in a couple of weeks because the chlorine will be gone and bad things can grow back.


Really not very afraid of that happening.


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