What target to use
The right free chlorine level depends on your CYA. A useful rule is to keep free chlorine at roughly 7.5% of CYA, so a pool at CYA 40 wants about 3 ppm and never below 2. Outdoor pools in full sun lose 2 to 4 ppm a day, which is why a daily dose is normal in summer.
Product strengths
Per 10,000 gallons, one gallon of 12.5% liquid chlorine raises free chlorine about 12.5 ppm. One pound of 65% cal-hypo raises it about 7.8 ppm, one pound of dichlor about 5.6 ppm, and one pound of trichlor about 9 ppm. Household bleach at 6% is half the strength of pool liquid, so you need twice as much.
Adding it
Pour liquid slowly in front of a return with the pump running. Never mix products in the same bucket, and never add water to acid or chlorine, always the other way round. Need to clear algae? Use the shock calculator instead.
Dose tables by pool size
Written-out amounts for every product: 5,000 gallons, 10,000 gallons, 12,000 gallons, 15,000 gallons, 18,000 gallons, 20,000 gallons, 25,000 gallons, 30,000 gallons.