Bleach Shelf Life

[zelmo]

Maybe this doesn't have an answer because of variables, but are there any guidelines on the shelf life of bleach? Say it is kept at 60 degrees in the dark and the retailer didn't have it too long and stored it correctly.

[bhale1518]

Can't help you with actual shelf life although i've had had several gallons carried over from previous seasons and i've used them to "shock" my pool in the spring. Won't hurt a thing, just might be a little weaker than normal. Doesn't really matter if your using the cheap stuff cause there's not much else in there that will affect anything else.

[KurtV]

Here's a link to a study of the shelf life of 5% NaOCl solution:
http://www.forp.usp.br/restauradora/soda/sodaingl.html

[zelmo]

That is great information. It indicates (to me, anyway) that I don't need to be too concerned as long as it isn't a batch from last year.

That does lead to another question, though. Don't some of the deep discount stores buy their stuff in closeouts, fire sales, old stock, etc.? Should we stick to "normal" retailers that have their own distribution systems so we are sure that it isn't a batch that has been around for awhile?

[waste]

Funny, I had the opportunity to talk to the son of the owner of the company we buy our shock from last year. He said that 'in the box' (ie protected from UV) it was at full strength for 90 days, and after that it degraded "slowly". I do not know about regular bleach, sold in the stores (I made sure that all the shock was taken back at the end of last season - who knows what they do with it, test it and resell it as 6% bleach?) . As a simple and easy test, look at it if it is very yellow/green, it's probably good - if it looks like water, it probably is (just water). Many liquid products are affected by UV, when I worked at a package (liquor- for the folks not in the NE) store, I learned that beer spoils with UV exposure, therefore beer in brown or green bottles will last longer. ( What's the use of having a beautiful pool without a case of cold beer to drink? )
Hope this is helpful, if not, rag on me mercilessly

[waterbear]

if you are testing your water whether the bleach has lost strenth becomes a bit moot. If you put it in and the FC is not where it is supposed to be then put in more! (or use it for washing your whites! )