Temperature will slightly affect the performance. The 145 chlorine test papers (0-200ppm) have been checked in solutions up to 70°C (158°F). At temperatures above 50°C, a 10ppm solution will not develop as much color as it should, resulting in a reading lower than expected. Solutions of 50, 100, and 200ppm chlorine appear to be influenced less. For practical purposes, solutions greater than 50ppm are not noticeably influenced by temperature.