Can you store it in a hot garage?

How can you tell if it is good or degraded?

What to look for when buying for water purification?

Source?

Lets see your Calcium Hypochlorite forts

Every time I've stored it it's destroyed the container it was stored in and
anything metal within a few feet of it.

If you want chlorine for disinfection I'd look at one of the salt generators.

If you do get it make sure it's just hypochlorite and nothing else.

Of course you can store it in a hot garage, it will just degrade faster, especially if the sealed container has been opened.  You may have to use several times the previous amount to get the same result as you did with a fresh batch.  There's no predicting, you just have to measure the chlorine residual in the final product and adjust.

My experience with the 'salt systems' for pools is that they are crap, work poorly and fail early.  I was an inspector for the State of Florida.  That type of system was examined and denied for permitting by our program office (as in no way, no time, no how).  They became allowed after a big hotel chain illegally changed over all their pools to salt and got caught, by me.  Two weeks later the big guys at the State Capitol decided that salt systems could be approved after all.

I'm referring to products specifically meant to create disinfection chlorine/peroxide solutions, not salt water pool systems,
e.g. the MSR SE200 (now discountinued), USB gadgets like this one, or the Aqua Research H2gO or similar systems.

All of them are designed to make a chlorine disinfecting solution for water purification from salt on a small scale,
and salt stores way better than hypochlorite does. (Just FYI, there's nothing really magic about these devices,
they're just doing electrolysis using electrodes like carbon that don't introduce toxic metal compounds into the
solution the way copper wire would.)

The principle is the same as pool systems, but the execution and purpose are completely different.

Have some stored away, watched a few videos about using it and seeing some variation in recommended dosing amounts, probably due to different manufacturers and formulation of the inert components.  Had some test strips made for doing bleach solution concentration testing, but looks like those are expired at this point.  

Gonna go check and see how mine is looking.  One of the recommendations was storing it inside a sealed 1 gallon bucket with a lid, inside a glass jar with a plastic top as it will eat thru the thin plastic packaging eventually over the years.  Can’t recall how mine is packaged…

It is easily the simplest and cheapest way to purify water, but you still need to filter it as well, or give it a full week of time, in order to wipe out protozoas.  I think filtering and chlorinating as separate steps would be easiest.

This, I just store water filters.

Some above linked items are reminiscent of the discontinued MSR Miox.

Yeah I use calcium hypochlorite for my pool.
Its easier than chlorine for me.  
plus I know it will sanitize water for drinking.
I woukd use pool water if I needed water.
Then filtered lake water as last resort.
It is stored on my patio in its original container.
I do notice it is corroding the "stainless" steel prep table it sits under.

thats all I know.

I had a small locker of it on every ship I was stationed on and only kept a few small plastic bottles worth on hand. It always corroded every steel locker it was stored in. I wouldn't store it anywhere near anything I don't want to corrode.

My pool shock eventually corroded the metal bail/handle on the plastic bucket, with Gamma seal lid installed, in which it was stored.

Despite all the corrosion issues, pool shock stores a hell of a lot better than a bottle of bleach, which is good for maybe 6 months or so.

Filtering may or may not get everything like viruses, so ideally you want to filter and then chlorinate if at all possible.

water filters alone do not disinfect water containing virus and some bacteria. It depends on size of the biological and the absolute filter resolution.

I'll take my chances with the filters I store over trying to store large quantities of chemicals to treat with chlorine compounds.

If somebody has a sustainable way to store those chemicals then I am all ears.

Probably a more sustainable way to kill the viruses, etc would be to use UV disinfection.

Problems to overcome with that are electricity generation and replacement bulbs, other spare parts, etc.

There used to be a seller on Amazon that sold 1lb bottles of the stuff in heavy duty containers with a screw off top. Ive had a couple those containers for years without any issues. Never a whiff of it and never any corrosion issues.

https://www.amazon.com/gp/aw/d/B01N54YNLW

Every other method ive tried eventually failed. Whatever container they used must have been designed for exactly that use.

Instead of calcium hypochlorite that is unstable use  sodium dichloro-s-triazinetrione also known as sodium dichlor.
Available from Amazon and approved for disinfecting drinking water. Sodium Dichloroisocyanurate in Drinking-water  WHO International Scheme to Evaluate Household Water Treatment Technologies It is shelf stable, wont cause metal corrosion if kept in a closed container and a little goes a long way.

You really do not need much.

a 1 pound plastic container of pool shock ( with no other active ingredients ) will sanitize tens of thousands of gallons of pre-filtered water. When you take out the organic material that a filter will remove, you need a lot less chlorine compound to sanitize the water.

I have kept calcium hypochlorite multiple "bagged" with no problems. original container in 2 zipplocked freezer bags inside another plastic tub with lid. Keeps it dry and a way from things it can rust.

I havent really noticed any issues with storing it. I have used the a bunch of the zip fizz plastic pop top containers to store smaller amounts but I probably have a hundred or so of them. Ive only had them in there for a couple of years and I put them all in another clear container and have them on a shelf inside. I do know I had one bag that was stored in the original thick plastic bag and that became really brittle in less than a year though.