How much chlorine should be in a hot tub?

Ideal range 3-5 ppm

When first starting a spa with Chlorinating Concentrate, test the free chlorine residual frequently to determine how often you will need to apply product.  Add 2 tsp. of per 200 gallons at a time with the pump running. Circulate 2 hours, then retest the free chlorine residual. Adjust as needed.

FreshWater Salt and FROG @ease SmartChlor have different instructions and ranges.  Consult their respective manuals for more information.