Chemical Sanitizer Concentration: The Numbers You Must Recall

Concentration that is too weak or too strong both fail

Chlorine (bleach): 50 to 99 ppm for food-contact surfaces in a three-compartment sink.
Quaternary ammonium: follow the manufacturer label, typically 150 to 400 ppm.
Iodine: 12.5 to 25 ppm.
Test strips must match the sanitizer in use and be stored dry.
Water above 110 F (43 C) degrades chlorine and shortens its useful life.