CPO Disinfection and Sanitizers Questions and Answers 2

Question 1

What is the minimum free chlorine residual required for a public swimming pool according to most state health codes?

Accepted Answer

1.0 ppm

Answer

Most state health codes require a minimum free chlorine residual of 1.0 ppm for public swimming pools.

Question 2

What is the difference between free chlorine and combined chlorine in pool water?

Accepted Answer

Free chlorine is available to sanitize while combined chlorine has reacted with nitrogen compounds

Answer

Free chlorine is the active sanitizer available to kill pathogens. Combined chlorine (chloramines) has already reacted with ammonia and nitrogen compounds.

Question 3

What process is used to eliminate chloramines from pool water?

Accepted Answer

Superchlorination or breakpoint chlorination

Answer

Breakpoint chlorination involves raising the free chlorine level to approximately 10 times the combined chlorine reading to oxidize chloramines.

Question 4

Which form of chlorine has the lowest pH and tends to lower pool water pH when added?

Accepted Answer

Trichlor (trichloroisocyanuric acid)

Answer

Trichlor has a very low pH of approximately 2.8 to 3.0, making it an acidic chlorine source that lowers pool water pH over time.

Question 5

What is the recommended maximum cyanuric acid level for outdoor public pools?

Accepted Answer

100 ppm

Answer

Most health codes recommend cyanuric acid levels not exceed 100 ppm, though many experts set the practical maximum at 70 to 90 ppm.

CPO (Certified Pool Operator Exam) Practice Test

CPO (Certified Pool Operator Exam) Practice Test

CPO Disinfection and Sanitizers Questions and Answers 2