Breakpoint Dose
The breakpoint dose is the specific amount of free chlorine that must be added to destroy all combined chlorine in pool water.
Definition
The breakpoint dose is the specific amount of free chlorine that must be added to destroy all combined chlorine in pool water.
Typical Values: Breakpoint dose = 10 × CC; typical: 5–15 ppm of additional FC
In Plain Language
Breakpoint dose = 10 × (combined chlorine reading in ppm). If CC = 0.8 ppm, breakpoint dose = 8 ppm of additional FC. The current FC level must be added to the breakpoint dose to determine the total target FC: if current FC is 1.5 ppm and breakpoint dose is 8 ppm, target FC = 9.5 ppm. Use the shock calculator to determine how many pounds of product are needed to reach this target for a specific pool volume.
Why It Matters
Calculating the exact breakpoint dose prevents under-dosing (which fails to destroy chloramines and wastes product) and over-dosing (which extends re-entry wait time).
Typical Values
Breakpoint dose = 10 × CC; typical: 5–15 ppm of additional FC
Last reviewed: 2026-06-01