Actual Potency of Fresh 12.5% Liquid Chlorine

[sparcel]

I assume that freshly made 12.5% liquid chlorine is actually a somewhat higher potency than 12.5% so that it will be at or above 12.5% for some period in a store. Does anyone know what that level is? A local pool store manager claimed to me that their HASA 12.5% chlorine is actually more like 18% initially, but I have no idea if he really knows that. I have a few reasons for asking. It may affect how often I buy chlorine (since, for example, 18% would degrade quickly and I would get more value if I bought it very fresh), and also, if I am calculating how much to add to my pool, it would be handy to have a ballpark rather than need to develop that knowledge from actual experience.

The brand easily available for me locally is HASA, and I know at least one of the local pool stores gets fresh supplies every couple days.

I have tried my hand as testing chlorine potency using the dilution 9999 to 1 method with FAS-DPD test mentioned here at TFP, but I've had trouble getting accuracy that I trust. (I should try my hand at this again.)

 

[YippeeSkippy]

I have read reports of people finding it a *bit* stronger than just 12%..... but no where near 18%.

Maddie

 

[ccbill]

Buy some ten percent and some 12-½ percent and experiment. Test your pool, add a gallon and test again. Do it with each and see how they differ. If you have a good feel for your pool volume you can do those calcs too.

I stopped using the pool store 12.5% after I got a batch that was definitely less than 10%. I'd been using it for a while and everything was fine, I was testing once a week then boom, my FC readings were low and it took me a while to figure out I had a bad batch of LC. I stopped buying from them but that was probably overkill, the real fix was testing more often.