How many days can a spa with a capacity of 1,850 gallons sustain an average of 100 bathers per day before noticing complaints of eye irritation and skin itching?

The correct answer indicates that a spa with a capacity of 1,850 gallons can sustain an average of 100 bathers per day for 6 days before issues such as eye irritation and skin itching become noticeable.

This is based on the understanding of water quality and bather load in recreational water facilities. The bather load is significant because the introduction of a large number of bathers increases the organic contaminants, body oils, lotions, and other residues in the water. Over time, these contaminants can surpass the spa's ability to effectively manage them with its filtration and sanitization systems.

Typically, spas have a recommended turnover rate, and the water chemistry must be monitored closely for factors such as chlorine levels, pH, total dissolved solids, and the presence of byproducts like chloramines, which are responsible for irritation and discomfort. The decision of 6 days reflects a balance between the capacity of the water to handle the waste produced by 100 bathers per day and the deterioration of water quality that leads to complaints.

In contrast, the other options of shorter or longer durations than 6 days suggest either an underestimation or overestimation of the spa's capacity to maintain acceptable water quality under the given conditions. Understanding the relationship between b