Calcium Hypochlorite

Here's a good article on how to mix and use calcium hypochlorite  to purify water. Make sure you use all safety precausions while using this chemical. Store calcium hypochlorite in its original container in a well ventilated area, very corrosive to metals, etc.

https://www.instructables.com/id/Pool-Shock-for-water-Purification/

Here is a MSDS sheet on calcium hypochlorite:

http://commercialaquaticsupplies.com/MSDS%20calcium%20hypochlorite.pdf

Dry 68% Calcium Hypochlorite Granules
https://grandpappy.org/hwater.htm

This is the shock treatment chemical used in swimming pools.
Kills Bacteria and Viruses.
Not effective against all Protozoa.
Does Not Neutralize Harmful Chemicals or Radioactive Particles.

The water should not be too cool. The water temperature should be 70°F or higher. If necessary, put the water in direct sunlight to raise the water temperature. The effectiveness of chlorine at killing pathogens diminishes rapidly at lower temperatures.

Put 1/96 of an ounce (a pinch between thumb and finger) of 68% Calcium Hypochlorite granules into one gallon of water. Wait one-hour. If you can detect a faint chlorine smell in the water, then it is safe to drink. If you can't smell the chlorine, then add another “pinch” and wait another hour. If you can detect a faint chlorine smell, then the water is safe to drink. If you still can't detect the smell of chlorine, then discard the water because it contains too many germs. (Note: Always start with a small amount of Calcium Hypochlorite and add a little more if necessary. Too much chlorine is harmful to your body.)

The shelf life of liquid bleach (sodium hypochlorite) is much shorter than the dry 68% Calcium Hypochlorite granules. Therefore, if you wish to store hypochlorite for emergency purposes, the best choice is the dry granules.

Liquid Bleach: If you have dry 68% Calcium Hypochlorite granules, and for some reason you need liquid bleach, then you may dissolve one-ounce of 68% granules in one-pint of water and you will have a 5.25% liquid bleach solution.

While I don't want to disparage grandpappy...

Never ever touch Calcium Hypochlorite granules with your bare fingers!

I have set aside various tiny plastic measuring spoons so I can make liquid bleach in small batches and then use that to make disinfecting spray (for pandemic preps) or disinfect water (any long duration event.) Those spoons are set aside because I don't want any residue on them that might react badly to the Calcium Hypochlorite...and plastic is essential since metal corrodes when around Calcium Hypochlorite.

Better than Bleach: Use Calcium Hypochlorite to Disinfect Water
https://readynutrition.com/resources/better-than-bleach-use-calcium-hypochlorite-to-disinfect-water_19062010/

This article was originally posted at Survival Topics

  Many outdoorsmen, survivalists, and households preparing for emergency disasters rely upon common household bleach as a disinfecting agent to make water safe to drink.

Bleach will destroy most (but NOT all!) disease causing organisms (boiling water to make it safe to drink is always the best method).

What is not well known is Calcium Hypochlorite is far better for chemically disinfecting water. ---CONTINUED---

You can use granular calcium hypochlorite to disinfect water.
https://www.epa.gov/ground-water-and-drinking-water



If you don’t have liquid bleach, you can use one of the other disinfection methods described below.

   Granular calcium hypochlorite. The first step is to make a chlorine solution that you will use to disinfect your water. For your safety, do it in a ventilated area and wear eye protection. Add one heaping teaspoon (approximately ¼ ounce) of high-test granular calcium hypochlorite (HTH) to two gallons of water and stir until the particles have dissolved. The mixture will produce a chlorine solution of approximately 500 milligrams per liter. To disinfect water, add one part of the chlorine solution to each 100 parts of water you are treating. This is about the same as adding 1 pint (16 ounces) of the chlorine solution to 12.5 gallons of water. If the chlorine taste is too strong, pour the water from one clean container to another and let it stand for a few hours before use. CAUTION: HTH is a very powerful oxidant. Follow the instructions on the label for safe handling and storage of this chemical.

Letter Re: Storing Dry Hypochlorite Bleach
https://survivalblog.com/letter-re-storing-dry-hypochlo/

By James Wesley, Rawles on March 4, 2011 12:07 AM
Dear Mr. Rawles -
Regarding the recent post on "Forever Preps"....

"Forever Prep #3: “Dry” Bleach This has often been covered by various sources on SurvivalBlog, but so-called “dry” bleach (pure Calcium Hypochlorite) lasts forever. If you go a little crazy and buy two 25 pound boxes of it from a big box store, you can make a solution that can purify about 4 million gallons of water! And, by the way, this Forever Prep is also very cheap (about $45-$50 for 25 pounds) and takes almost no storage space.

You must . . . ---CONTINUED---

Bleach Shortage? Here’s How to Make Bleach from Pool Shock (and How to Purify Water With It)
https://www.theorganicprepper.com/how-to-make-bleach-from-pool-shock/

  (SNIP) ... you can make your own bleach with granular calcium hypochlorite, the primary component of typical pool shock. It’s essential to confirm that your pool shock is not contaminated by other chemicals, such as algicides. Only HTH is acceptable for purifying your water. ---CONTINUED---

I've seen both Sodium Hypochlorite and Calcium Hypochlorite mentioned in making bleach soloutions. Here's the difference between the two:

Difference Between Sodium Hypochlorite And Calcium Hypochlorite
https://poolcareguy.com/sodium-hypochlorite-pool/

Both sodium hypochlorite and calcium hypochlorite are disinfectants, but the products are actually a little different.

Calcium hypochlorite, or cal-hypo, as it is often called, contains calcium, whereas sodium hypochlorite does not. ---CONTINUED---

How to Use Calcium Hypochlorite for Water Purification
https://thesurvivalmom.com/more-information-about-the-use-of-calcium-hypochlorite-for-water-purification/

hen I was writing my book, Survival Mom, I was a real stickler for accuracy. Chapter 2 is all about water storage and purification, so I went to water expert Alan Martindale who is the Water Quality Supervisor for the City of Mesa in Arizona with all my unanswered questions about water safety.

I asked Alan about the use of calcium hypochlorite, aka pool shock, for purifying water because I wanted an expert to weigh in on this popular survival and prepper topic. I’ve written directions for its use in purifying water here.

Here is what Alan had to say: ---CONTINUED---

Calcium Hypochlorite for Treating Drinking Water, The Good and the Bad
https://preparednessadvice.com/calcium-hypochlorite-treating-drinking-water-good-bad/

For several years, I have seen many people recommending calcium hypochlorite for water purification. They are providing correct information in that calcium hypochlorite will treat water if used correctly. A pound of it will treat thousands of gallons of water and will cost you less than $10.

Before you rush out to buy some, I want to warn you about a few things that can get you into trouble or even killed.

Proper precautions must be taken while handling and storing calcium hypochlorite. Always follow the manufacturer’s instructions. Calcium hypochlorite is a highly reactive material ... ---CONTINUED---

Disinfecting Water Using Calcium Hypochlorite
https://theprovidentprepper.org/disinfecting-water-using-calcium-hypochlorite/

(SNIP) ... The following is the EPA guidelines on using calcium hypochlorite to disinfect water.

You can use granular calcium hypochlorite to disinfect water. ---CONTINUED---

Safely Purify Water with Calcium Hypochlorite (+ Pros/Cons)
https://geekprepper.com/disinfect-water-with-calcium-hypochlorite/

Boiling your Water is the easiest way to make it safe. Bleach (ONLY Calcium Hypochlorite bleach) can also be used to make safe drinking water, but bleach has a shelf life of less than 2 years.

You can use the active ingredient from bleach and disinfect water with Calcium Hypochlorite. ---CONTINUED---

Using Calcium Hypochlorite to Disinfect Water
https://preparednessadvice.com/using-calcium-hypochlorite-to-disinfect-water/

Personally, I avoid the use of all chlorines whenever possible.  There are filters on my water system at home to eliminate it. I believe there are better ways of filtering or purifying water in an emergency.

But for the benefit of people who choose to use it.  The following is the EPA guidelines on using calcium hypochlorite  to disinfect water.

You can use granular calcium hypochlorite to disinfect water.  ---CONTINUED---

EMERGENCY DISINFECTION OF DRINKING WATER
https://www.epa.gov/sites/production/files/2017-09/documents/emergency_disinfection_of_drinking_water_sept2017.pdf

(See page 2 of the pdf file)

Granular calcium hypochlorite.The first step is to make a chlorine solution that you will use to disinfect your water.For your safety, do itin a ventilated area and wear eye protection. ---CONTINUED---

Here is a little information on chlorine concentrations in water. While the jargon isn't extreme, it is a bit steep for a non-science reader, so if I get the chance, I will write a discussion summary useful for preppers, in laymen's language, later.
https://www.cdc.gov/safewater/chlorine-residual-testing.html

Referencing the page I linked to, above. This page is one of a booklet on producing Safe Water, in 3rd World countries, or places with similar problems.

The article relies heavily on being able to test the water after adding chlorine to it. The two tests discussed were 30 minutes and 24 hours after adding chlorine.

There is another page:
https://www.cdc.gov/safewater/chlorination.html
which discusses pro's and con's of chlorine treatment.
Along the Left side of the page there are links to 5 other articles, one of which I linked to, above.

One of those pages discusses pre-treatment, to reduce the visible contaminates in the water. This reduces the amount of chlorine needed.  

Basically, the rule of thumb is that after more than half an hour, you should still have a faint "waft" (scent) of chlorine present. If you have test strips available, look for 2ppm (2mg/l) after half an hour.

EPA sets maximum levels at 4ppm, and at that level it will smell like a public swimming pool. (see note) Simply leaving the cap loose overnight will reduce the chlorine content, substantially, which is the reason for the two standards listed above.


(Note: be aware, tho, that the smell usually associated with a public swimming pool often means that there isn't enough chlorine remaining in the pool.)