Shelf Life of calcium hypochlorite vs bleach (sodium hypochlorite)

[pratzert]

Hi All.

Does anyone (Ben?) know how the "Shelf Lives" compare between Liquid Bleach and powdered Cal-Hypo?

I am thinking of buying a 50 pound bucket of Cal-Hypo for shocking the pool but I think it may take a couple of seasons to use that much powdered shock.

Thanks.

[PoolDoc]

Don't do it.

Cal hypo keeps better than bleach but not THAT well. I can't tell you how many times I've opened a 100# barrel of cal hypo that was a couple of years old, and found a nice, visible, cloud of chlorine gas resting on top!

Neither cal hypo nor bleach can be safely stored for a year or more. The only product I know of that seems to do OK like that are the heat sealed bags of dichlor that Sams Club sells. Other brands may be OK, too. I just don't have the experience!

[pratzert]

Thanks for the info Ben.

I'll stick with the "fresh" Sodium Chlorite purchased each season to avoid any products going "stake".

Regards.

[PoolDoc]

Actually, you don't want to purchase sodium hypochlorite in bulk ("sodium chlorite" is a thing, but not what you are getting). Bleach, or sodium hypochlorite, breaks down rapidly at temperatures over 80 degrees, so it's best to store it where it is cool.

Recent changes in bleach manufacturing have improved the shelf life, but you still don't want to 'stock up' in May, for the August heat wave!

[pratzert]

Thanks Ben.

I'll make a conscious effort to not "stock up" on chemicals for the entire season and buy every couple of weeks for what I need.

That way I won't have any products use their potency much over time until I use them.

[robbym70]

I'm buying a case (four gallons) of 12% sodium hypochlorite (labeled as shock) I go through this in about 3-4 weeks or so. Generally dosing with about 40 -50 ounces every couple of days. I'm guessing that's a tolerable rate to avoid breaking down? CYA is about 30 or so.

[PoolDoc]

Yeah. Just try to keep the bleach out of sunlight, and in the coolest available spot.

[robbym70]

thanks !