Liquid chlorine (sodium hypochlorite)
Also called: sodium hypochlorite, bleach, pool chlorine jugs.
Liquid chlorine is sodium hypochlorite in water, sold for pools at about 10–12.5% strength. Household bleach is the same chemical at about 6–8.25%. Liquid chlorine adds only chlorine and a trace of salt, so nothing accumulates in the pool water.
Why it matters
Every chlorine source delivers the same active sanitizer. What differs is what else comes with it. Tablets add stabilizer and acid, cal-hypo adds calcium, and liquid adds nothing that builds up, so you set CYA once and control it separately. It nets out roughly pH-neutral over a full cycle. The catch is freshness: hypochlorite fades with heat and time, so the percent on the label is a when-fresh maximum. Buy it fresh and do not stockpile jugs in a hot garage. If you use bleach, use plain, unscented bleach only.
In numbers
Raising free chlorine by 10 ppm in 10,000 gallons takes about 107 fluid ounces of 12.5% liquid chlorine, or about 162 fluid ounces of 8.25% bleach.