Letter Re: Storing Calcium Hypochlorite


I was wondering if there was a better way of storing Calcium Hypochlorite? [POOLIFE TurboShock 78% Pool Shock 1 lb]

  1. Glass stopper bottles
  2. Would using a 1/2 gallon Ball [“Mason style”] jar and Tattler plastic lid be a workable alternative?

I forgot to repackage some that I bought a couple of years ago. It was fine at the beginning of hurricane season, but isn’t anymore. Shame on me. I’m glad I stored it on a shelf by itself.

  • How did the Tattler plastic lids on Mason jars do?
  • Does it need to be vented annually?

– T.J.

HJL’s Comment:

I actually no longer store the Calcium Hypochlorite. it just doesn’t seem to matter how you try to store it, you always end up with problems. If there is any exposed metal even near the storage container, it oxidizes. Even when using glass containers I’ve had issues. If I didn’t have leaks with them, I ended up dropping one every so often. It was just painful.

About two years ago one of our readers recommended the MSR SE200 chlorine generator to me. I reviewed it on the blog and ever since then it provides all of our chlorine needs. With this device, I no longer have to worry about the purity of the chemical and what additives the manufacture has added that might work against me. I even take it with us when we travel rather than buying bleach for dishes or cleaning. Table salt is so much easier to store than Calcium Hypochlorite!

I have modified mine to put Anderson Power Pole connectors on it so it is standardized with all of my 12V electronics. Considering how inexpensively you can assemble a 12V solar system, I really believe this is the way to go.


  1. I too have purchase a chlorine generator instead of storing chlorine in any form. I was surprised at the cost of the unit you own. I purchased mine from http://swimforhim.org/chlorine-producing-unit/ for $50. I also donated another $50. It works fine and is easy to use. I do not have anything to compare it to so your unit may well be worth the price difference. One thing to remember is all salt water swimming pools have a chlorine generator inline with the filtration system. In a SHTF situation you might be able to scavenge a unit. Since they have no moving parts, as long as the plates are clean and you have the appropriate power source, they should work.

    1. @Travis,
      I learned of that particular unit only after I had already purchased the MSR unit. I can see why there is the price difference, but it really just depends on how much involvement you want. The MSR unit is designed to be easy to use. In effect, you have a clear bottle with instructions to add salt to a certain level, then water to a certain level. You then pour the brine into the generator to a certain level and push the button. Five minutes later, you are ready to go with chlorine. It has little LEDs that inform you of the status along the way. If you are making more than one batch, you store the chlorine solution in the brown bottle (for up to 24 hours.
      The S.W.I.M. unit is a pour-through unit. You have to repeatedly pour your brine through the device to obtain the proper concentration. While they both produce the same product, the S.W.I.M unit is a more manual process.
      The MSR is designed to be used when there may be significant communication barriers (language) between the person needing it and the person providing it (like in humanitarian efforts). You get the same end product, the MSR is just easier to use. I was happy enough with the MSR that I bought a second unit (two is one, one is none), but you will be fine with the S.W.I.M unit.

  2. How to store Calcium (or sodium) hypochlorite?


    It’s an oxidizer, and oxidizers are unstable. the hypochlorite will break down and release chlorine gradually and build up pressure within the storage vessel, and cause leaks, which will corrode any metal in the vicinity.

    I tried storing some in an acrylic jar with an acrylic lid, and silicone gasket that was closed by the traditional thick metal wire clamp. I even bent the clamp a bit to make the seal even tighter. In about 6 months I could see that the hypochlorite inside was changing and the chromed steel wire clamp was very rusty.

  3. I’ve found a reasonable solution for storing calcium hypochlortie.

    First I left it in the bag in which it was packaged. That lasted for maybe a year. It was a one pound bag. Then I noticed the bag was deteriorating and that it oxidized/corroded the 55g aluminum barrel wrench near it.

    Next I tried mason jars with the standard metal lids and rings. Those lasted a few days.

    Then I tried mason jars with tattler lids. Those deteriorated after a few days.

    I considered ground-glass stopper bottles but I was concerned if there was a build up of gas that it would push the stopper up and leak. Plus glass can break and shatter easily.

    I tried a used chlorox jug. That lasted a little while but it started to become brittle.

    Finally I tried a used laundry detergent bottle. That has successfully held about 1 cup of CH pellets (each approximately .8cm in diameter) for two years. I just checked it (outside). The color of the container has faded a little but it’s still very solid. I was letting it sit on the floor next to a metal storage rack the entire time and the rack has no signs of oxidation/deteriorate at all. I have never smelled chlorine so the cap has maintained a good seal. I should note that I gave most of the CH away (all but about a cup) to a guy that had a pool. I was concerned when I couldn’t find a storage container to safely hold it.

    I recommend you use a funnel when filling/transferring from one container to another. I cut the bottom off of the chlorox jug and used that.

    I always work outside, stand upwind, and wear safety gear. Those fumes are concentrated. Chlorine gas + water = hypochlorous acid. There is water in your eyes, nasal passages, and lungs!

  4. I purchased glass bottles with ground glass stoppers from Amazon, I only had a few bags so this was a very easy solution to storage. As I recall, they were very reasonable. I placed the jars in a short box to stabilize them and added a bunch of copied instructions on how to use it, don’t forget to label those bottles.

  5. A local (for me) Louisville KY company waterstep.org sells similar gear as part of their mission to provide safe water to communities in developing countries. A chlorine generator for $250 that can produce a gallon an hour. And a very interesting and very expensive chlorine gas generator that also produces sodium hydroxide aka lye. They call it the M-100 Chlorine Generator.

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