Quote Originally Posted by giroup01 View Post
On the bleach bottle you read the % concentration of sodium hypochlorite.
What you are measuring is the concentration available chlorine content.

Not the same thing.
What is the point of that?

The whole point of the calculation is to determine how much available chlorine the Bleach/Liquid Chlorine will deliver. Ultimately, that's what you need to sanitize your pool, and the concentration is merely a guide to get you there.

Parts Per Million added = (1,000,000 / pool volume) * (Bleach or LC Concentration (as a decimal)) * (amount of bleach or LC used)

If you add 1 ml of bleach or LC to 10 liters of water the resultant Parts Per Million measured, less the public water's residual FC is = to the concentration of the bleach bottle.

What's the problem?

Carl