Testing Bleach Strength

Back in my previous life (about 1969) I worked at a chemical company in the Houston area that made industrial strength Sodium Hypochlorite. I think we used a hydrometer to test percent ---- I'm not sure I remember anymore.

Can we test what we buy easily. If you don't know if it's fresh it's kind of a crap shoot using the calculator.

Maybe I worry too much. :)

I kinow hydrometers are used to test the strength of hydrogen peroxide. Never heard of them used for sodium hypochlorite (but they might be). There are chemical tests (titrations) that are commenly used to test the stength of bleach. Taylor Technologies has some listed on their website (but not in the pool/spa secton.)