CPO Pool Maintenance and Troubleshooting 2

Question 1

Pool water appears cloudy despite free chlorine and pH being within normal range. What is the most likely cause?

Accepted Answer

Poor filtration or inadequate water circulation

Answer

When chlorine and pH are normal, cloudy water typically results from poor filtration efficiency or insufficient circulation rather than chemical imbalance.

Question 2

A pool has developed a widespread green algae bloom. What is the recommended initial treatment?

Accepted Answer

Shock the pool with chlorine at approximately 10 times the normal dose

Answer

Shocking with a heavy chlorine dose is the first-line treatment to kill green algae, followed by brushing surfaces and filtering out dead algae.

Question 3

Mustard (yellow) algae is particularly difficult to eliminate because it:

Accepted Answer

Is resistant to normal chlorine levels and clings tightly to pool walls

Answer

Mustard algae is chlorine-resistant at normal concentrations and adheres stubbornly to surfaces, requiring aggressive shock treatment and thorough brushing.

Question 4

Black algae is the most difficult pool algae to eliminate primarily because:

Accepted Answer

It has a protective outer layer and deep roots that penetrate porous surfaces

Answer

Black algae's waxy protective coating and deep roots in plaster require aggressive physical brushing and very high chlorine concentrations to penetrate and kill.

Question 5

A sand filter's clean operating pressure is 10 psi. At what pressure reading should backwashing be initiated?

Accepted Answer

15–18 psi (5–8 psi above clean starting pressure)

Answer

Backwashing should occur when pressure rises 5–8 psi above the clean baseline, indicating sufficient dirt accumulation to reduce filtration efficiency.

CPO (Certified Pool Operator Exam) Practice Test

CPO (Certified Pool Operator Exam) Practice Test

CPO Pool Maintenance and Troubleshooting 2