CPI Commercial Pool Operator Standards 2 — Questions and Answers
Question 1: What is the minimum required turnover rate for a commercial swimming pool under most state health codes?
- 6 hours (Correct answer)
- 8 hours
- 12 hours
- 24 hours
Correct answer: 6 hours
Most state codes require the entire pool volume to turn over (be recirculated through filtration) at least once every 6 hours for swimming pools.
Question 2: A commercial pool operator discovers the CYA (cyanuric acid) level is 120 ppm. What is the most appropriate corrective action?
- Add more chlorine to compensate
- Partially drain and refill the pool (Correct answer)
- Add a CYA reducer chemical
- Increase UV exposure by removing the pool cover
Correct answer: Partially drain and refill the pool
When CYA exceeds recommended levels (typically 30–50 ppm), partial draining and refilling with fresh water is the only effective way to dilute it.
Question 3: Under ADA requirements, which of the following is an acceptable means of pool access for persons with disabilities in a newly constructed commercial pool with over 300 linear feet of pool wall?
- One pool lift only
- One sloped entry only
- At least two accessible means of entry (Correct answer)
- A ramp installed on the deck
Correct answer: At least two accessible means of entry
ADA requires that pools with over 300 linear feet of pool wall provide at least two accessible means of entry, such as a lift and a sloped entry.
Question 4: What does a high combined chlorine (chloramine) reading above 0.2 ppm typically indicate in a commercial pool?
- Excess free chlorine
- Insufficient bather load
- Inadequate chlorine to oxidize nitrogen-containing contaminants (Correct answer)
- Overly high pH
Correct answer: Inadequate chlorine to oxidize nitrogen-containing contaminants
High combined chlorine indicates that free chlorine is reacting with nitrogen-containing bather waste (urine, sweat) and is not present in sufficient quantity to fully oxidize these contaminants.
Question 5: Which type of filter medium requires the highest operating pressure before backwashing is needed?
- Sand filter
- DE (diatomaceous earth) filter (Correct answer)
- Cartridge filter
- Zeolite filter
Correct answer: DE (diatomaceous earth) filter
DE filters operate at lower initial pressures but have very fine filtration, so they can actually reach backwash pressure thresholds more quickly; however, cartridge filters have no backwash cycle and DE filters require backwash at a 7–10 psi rise — the principle is the same for sand but DE achieves finer filtration.
Question 6: A commercial pool's flow meter reads significantly lower than normal with no change in valve positions. What is the most likely cause?
- Increased bather load
- Clogged or dirty filter (Correct answer)
- High free chlorine level
- Elevated water temperature
Correct answer: Clogged or dirty filter
A significant drop in flow rate with no valve changes typically indicates a clogged or dirty filter that is restricting water flow through the recirculation system.
Question 7: What is the primary purpose of a commercial pool's surge tank or balance tank?
- To store extra chlorine solution
- To accommodate water displaced by bathers and wave action (Correct answer)
- To heat water before it enters the pool
- To store backwash water for reuse
Correct answer: To accommodate water displaced by bathers and wave action
A surge or balance tank accommodates the volume of water displaced when bathers enter the pool, preventing water from overflowing the deck and maintaining proper water levels for skimmer function.
CPI Commercial Pool Operator Standards 2
What is the minimum required turnover rate for a commercial swimming pool under most state health codes?