Breakpoint Chlorination Dose
Combined chlorine (chloramines) = total - free, and the breakpoint shock dose = ratio x combined (commonly 10:1). Total 1.5, free 1.0 -> 0.5 ppm combined, a 5 ppm shock; shock past breakpoint (a partial dose worsens it). The label and testing govern.
Formula and source
combined = total - free; dose_ppm = ratio x combined (ratio ~10); optional lb_product = dose_ppm x (gal/1e6) x 8.34 / (avail/100).
The breakpoint (superchlorination) chlorination rule and Standard Methods 4500-Cl, by name.
Audience
This tile is built for trades and the adjacent professions in the Water and Wastewater Operations group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.