What does total chlorine measure in pool water?

Total chlorine measures the complete amount of chlorine present in pool water, encompassing both free available chlorine and combined chlorine. Free available chlorine refers to the chlorine that is actively doing the work of disinfecting and sanitizing the water, while combined chlorine consists of chlorine that has already reacted with contaminants and is no longer effective for disinfection.

By measuring total chlorine, operators can determine the overall chlorine levels in the pool and assess the effectiveness of the sanitation process. This measurement is crucial for maintaining safe swimming conditions, as it helps ensure the pool is adequately disinfected and can indicate whether additional treatments, such as shocking the pool to remove combined chlorine, are necessary.

The other options focus narrowly on either free or combined chlorine specifically, missing the comprehensive scope that total chlorine provides. Additionally, the mention of evaporated chlorine does not pertain to chlorine measurements in pool water, as evaporation is not a relevant factor in determining chlorine levels within the water itself.