Which statement correctly describes iodine usage parameters?

• A. Minimum temp 68°F, pH 5.0 or less, concentration 12.5-25 mg/L
• B. Minimum temp 75°F, pH 6.0 or less, concentration 50 mg/L
• C. Minimum temp 60°F, pH 7.0 or more, concentration 100 mg/L
• D. Minimum temp 80°F, pH 4.0 or less, concentration 200 mg/L

Answer: (A)

Iodine sanitizers work best when the solution is acidic, warm enough to support the chemistry, and at a concentration that provides effective disinfection without excess residue. When pH is kept at 5.0 or lower, iodine remains in the active form (hypoiodous acid) more effectively, delivering stronger antimicrobial action. A minimum temperature around 68°F helps the reaction proceed at a reliable rate, and a concentration of 12.5-25 mg/L is considered appropriate for producing the desired sanitizing effect without overuse. This combination—pH 5.0 or less, at least 68°F, and 12.5-25 mg/L—fits the typical guidance for iodine usage parameters, making it the best choice. The other options either propose a less acidic environment, a concentration outside the effective range, or a temperature that doesn’t align with the recommended conditions, which would reduce iodine’s effectiveness.