When should the first water test be conducted for a pool?

Conducting the first water test 1/2 hour prior to opening the pool is crucial for ensuring safety and water quality for swimmers. This timing allows operators to evaluate the chemical balance and clarity of the water, ensuring that it meets health and safety standards before guests arrive. It provides adequate time to make necessary adjustments to chemical levels if any issues are detected. This proactive approach helps prevent potential health risks associated with poor water quality, such as skin irritations or other illnesses caused by contamination.

The other options may not allow for sufficient time to address any water quality issues. For instance, testing immediately after closing could potentially miss any necessary adjustments needed before reopening. Testing an hour prior to opening might not give enough time for corrective actions. Hence, the choice of testing 1/2 hour prior strikes the right balance between assessment and corrective measures.