CPO Case Analysis & Practical Application 2

Question 1

A pool operator notices the water is cloudy and the filter pressure gauge reads 12 psi above the clean starting pressure. What is the FIRST corrective action?

Accepted Answer

Backwash or clean the filter

Answer

A filter pressure reading 8–10 psi above the clean baseline indicates the filter is dirty and should be backwashed or cleaned before other treatments.

Question 2

During a routine inspection a CPO finds the pool pH is 8.4 and chlorine residual is 1.5 ppm. Swimmers report eye irritation. What is the most likely cause?

Accepted Answer

High pH is reducing the effectiveness of the available chlorine

Answer

At pH 8.4 only about 3% of chlorine exists as hypochlorous acid (the active sanitizer), making it far less effective and potentially causing irritation due to inadequate disinfection.

Question 3

A hotel spa pool holds 2,000 gallons and the bather load is 10 people at a time. The required turnover rate is 30 minutes. What minimum flow rate must the circulation pump deliver?

Accepted Answer

67 GPM

Answer

Flow rate = volume ÷ turnover time = 2,000 gal ÷ 30 min ≈ 67 GPM.

Question 4

A CPO measures total alkalinity at 40 ppm. Which condition is MOST likely to result from this reading?

Accepted Answer

pH drift and difficulty maintaining stable pH

Answer

Low total alkalinity (below 80 ppm) acts as a poor buffer, causing rapid and unpredictable pH fluctuations that are hard to control.

Question 5

After a fecal incident involving formed stool in a public pool, what is the recommended free chlorine level and contact time for remediation according to CDC guidelines?

Accepted Answer

2 ppm for 25 minutes at pH 7.5

Answer

CDC recommends raising free chlorine to 2 ppm and maintaining it for 25 minutes at pH 7.5 or below to inactivate pathogens from a formed-stool fecal incident.

(CPO) Certified Pool and Spa Operator Practice Test

(CPO) Certified Pool and Spa Operator Practice Test

CPO Case Analysis & Practical Application 2