The formula (Volume of Pool / Pump Flow Rate (GPM) x 60 min) = turnover rate, will tell us:

The formula given is designed to calculate the turnover rate of a swimming pool, which is specifically defined as the amount of time it takes for the entire volume of water in the pool to be circulated through the filtration system. This is an important measure in pool management as it indicates how effectively the water is being filtered and sanitized.

When you divide the total volume of the pool by the pump flow rate (in gallons per minute) and multiply by 60, you convert the flow rate into a time frame, thus providing the number of minutes (or hours) it takes for the entire volume to circulate. A proper turnover rate is crucial for maintaining water quality, clarity, and safety for swimmers.

While the other choices deal with different aspects related to pool operations, they do not directly relate to the concept of turnover rate. Efficiency of pumps, flow rates, and chlorine demand are all relevant factors in the overall management of a pool system, but they do not measure the time taken for water circulation as indicated by the provided formula.