Final answer:
The minimum water temperature for iodine to be an effective sanitizer at a concentration of 12.5 ppm is 60-80 °C (140-176 °F).
Step-by-step explanation:
The minimum water temperature for iodine to be an effective sanitizer at a concentration of 12.5 ppm depends on several factors. However, iodine is generally most effective as a sanitizer at a temperature range of 60-80 °C (140-176 °F).