Test chlorin strength?

[xoroniox]

Im curious to find out if there is a way to test the strength of bleach, my local pool store sells 10.5% bleach for $3.77/jug 2.5gallon. one of the employees told me they get refills every 2-3weeks! so i am curious if its still 10.5% they do keep it in a huge tank, indoors/ac. anyway is there an easy test to check strength of chlorine? Thanks for the help

-Arron

[Poconos]

Interesting question. If you have a way to measure small quantities accurately, like 0.1 ml or even a milliliter, then you can do repeated dilutions. Diabetic hypo needles are great for this. 10% chlorine would be 100,000 PPM, so if you take 1 liter of unchlorinated water and add 1 ml of 10% chlorine you get to 1000 PPM. Keep diluting until you get to something like 10 PPM or so, that you can measure. Sounds like a good experiment for this morning.
Al

For what it's worth. Just did a check of some 6% Walmart Ultra that's been sitting around for a couple months. First diluted 2000:1, then 5:1 which is an overall of 10,000:1. Got 3.6% (3.6 PPM read with a Taylor K-2006) Hmmm ! Will continue to pursue this issue. Now I'm really curious.

[CrisL]

You could also get a rough estimate by adding the bleach to a clean and stable pool with a known amount of water and a known amount of chlorine in the evening and test in an hour or two after the pool circulated. A gallon of 10% bleach should raise a 20,000 gallon pool 5 ppm. Not exact, but you could surely tell the difference between 10.5% and say 6% or 7%.