NPLQ NPLQ Water Quality and Chemical Management Questions and Answers

Question 1

What is the recommended free chlorine level for a public swimming pool in the US?

Accepted Answer

1–3 ppm

Answer

5–8 ppm

Answer

0.1–0.5 ppm

Answer

10–15 ppm

Question 2

What pH range is considered optimal for pool water?

Accepted Answer

7.2–7.8

Answer

6.0–6.5

Answer

8.5–9.0

Answer

5.0–5.5

Question 3

What is the primary purpose of cyanuric acid (stabilizer) in outdoor pool water?

Accepted Answer

To protect chlorine from UV degradation

Answer

To raise pH levels

Answer

To lower total alkalinity

Answer

To kill algae directly

Question 4

What is the main purpose of 'shocking' (superchlorinating) a pool?

Accepted Answer

To destroy combined chlorine and organic contaminants

Answer

To lower the water temperature

Answer

To increase total alkalinity

Answer

To add stabilizer to the water

Question 5

What is 'combined chlorine' in pool water?

Accepted Answer

Chlorine that has reacted with nitrogen compounds and is less effective

Answer

Chlorine added directly to the pool

Answer

The total of free and bound chlorine

Answer

Chlorine that is stored before use

Question 6

What effect does a high pH (above 7.8) have on pool water?

Accepted Answer

It reduces chlorine effectiveness and can cause scale formation

Answer

It increases chlorine effectiveness

Answer

It prevents algae growth

Answer

It lowers total dissolved solids