CPO Pool Water Chemistry Questions and Answers 2

Question 1

What is the ideal pH range for a chlorinated swimming pool?

Accepted Answer

7.2 to 7.6

Answer

The ideal pH range is 7.2 to 7.6, with 7.4 to 7.6 being optimal for chlorine effectiveness and swimmer comfort.

Question 2

What is the function of total alkalinity in pool water chemistry?

Accepted Answer

To act as a pH buffer resisting rapid pH changes

Answer

Total alkalinity acts as a buffer system that resists rapid changes in pH. The ideal range is typically 80 to 120 ppm.

Question 3

What causes high pH in pool water and how should it be corrected?

Accepted Answer

Aeration, high-pH chemical additions, or high alkalinity; add muriatic acid or sodium bisulfate

Answer

High pH results from aeration causing CO2 loss, use of high-pH chemicals like sodium hypochlorite, or high alkalinity. Correct with muriatic acid or sodium bisulfate.

Question 4

What is the recommended calcium hardness range for a plaster pool?

Accepted Answer

200 to 400 ppm

Answer

Calcium hardness should be maintained between 200 and 400 ppm for plaster pools to protect the surface from dissolution.

Question 5

What chemical is used to raise total alkalinity without significantly affecting pH?

Accepted Answer

Sodium bicarbonate (baking soda)

Answer

Sodium bicarbonate raises total alkalinity with minimal impact on pH. Soda ash raises both pH and alkalinity significantly.

CPO (Certified Pool Operator Exam) Practice Test

CPO (Certified Pool Operator Exam) Practice Test

CPO Pool Water Chemistry Questions and Answers 2