Old Chlorine

[cjpwalker]

I've read here in several places that I want to make sure my bleach is fresh, or it isn't effective...

My question is, if I use an old bottle of bleach will it still register on a test as FC giving a false sense of security, or will it just take a lot more than it should?

 

[aswarren628]

It'll just take a lot more than it should. This thread gives good info on this subject. Breakdown of bleach over time by storage temperature - Page 2


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[cjpwalker]

Thanks... so I'll keep any extra I have after closing, and use it up next spring accordingly... I printed out Chem Geek's chart - wow, and thank you to him and the time on his hands!

 

[MarianParoo]

It will degrade even more by spring. If you use it now, which I recommend, you can test a half hour or so later and see where your addition ended up. Then you can work backwards in PoolMath to see the effective strength of the old stuff.

 

[singingpond]

We move the left-over pool chlorine to the laundry room at the end of the pool season, diluting it with an equal part water for laundry use.

 

[cjpwalker]

We move the left-over pool chlorine to the laundry room at the end of the pool season, diluting it with an equal part water for laundry use.

Yeah, laundry here is on an ozone generator ("activated oxygen" if you ask the marketing folks...) so we rarely add anything else. Only have a couple of gallons of bleach, but I'm going to stick with pucks for the rest of the season to get my CYA up.

Like I said, I'll pour it in the pool rather than throw it away. I can deal with weak - just wanted to make sure it didn't go bad.

 

[singingpond]

No, it doesn't go bad. We had some left-over 12.5% last fall (more than what we used on laundry over the winter). When we opened the pool in June I used the left-overs, and found it seemed at about the strength of supermarket bleach (5-6%). Worked fine, just had to use more.

 

[camueller]

It doesn't go bad, and if you store it out of the sun and heat over the winter, it'll still be plenty strong by spring. It just won't be as strong as it was new. I'd save it indoors and use it to open the pool in the spring, then buy new to start daily dosing.