CA QAL/QAC Category F Aquatic Exam |
Questions and Answers | 2026 Update |
100% Correct
1. The primary purpose of a skimmer in a swimming pool is to:
a) Add chlorine to the water
b) Remove debris from the water surface
c) Circulate water through the filter
d) Heat the pool water
Correct answer: b) Remove debris from the water surface
Explanation: Skimmers draw water from the surface, catching leaves, oils, and
other floating debris before they sink.
2. Which chemical is commonly used to increase the pH level in pool water?
a) Muriatic acid
b) Sodium bicarbonate
c) Sodium hypochlorite
d) Calcium chloride
Correct answer: b) Sodium bicarbonate
Explanation: Sodium bicarbonate (baking soda) raises pH with minimal effect on
alkalinity, unlike sodium carbonate which raises both more significantly.
3. The turnover rate for a public swimming pool is defined as:
a) The time required to filter the entire volume of water
b) The rate at which swimmers enter and exit the pool
c) The frequency of backwashing the filter
d) The rate of chemical addition
Correct answer: a) The time required to filter the entire volume of water
, Explanation: Turnover rate ensures all pool water passes through the filtration
system within a specified time to maintain clarity and hygiene.
4. Combined chlorine in a pool refers to:
a) Free chlorine only
b) Chlorine that has reacted with contaminants
c) The total of calcium and chlorine
d) Chlorine bound to cyanuric acid
Correct answer: b) Chlorine that has reacted with contaminants
Explanation: Combined chlorine is chlorine that has combined with ammonia or
nitrogen compounds, forming chloramines, which cause eye irritation and odor.
5. What is the ideal range for pH in a swimming pool?
a) 6.0–6.8
b) 7.2–7.8
c) 8.0–8.5
d) 5.5–6.5
Correct answer: b) 7.2–7.8
Explanation: pH within 7.2–7.8 ensures bather comfort, optimal chlorine
effectiveness, and prevents corrosion or scaling.
6. Cyanuric acid in pool water serves to:
a) Increase pH
b) Stabilize chlorine from sunlight degradation
c) Prevent calcium scaling
d) Remove metals
Correct answer: b) Stabilize chlorine from sunlight degradation
Explanation: Cyanuric acid acts as a stabilizer, protecting free chlorine from rapid
loss due to ultraviolet rays.
7. Which of the following is a symptom of high total alkalinity?
a) Rapid pH fluctuations
b) Cloudy water and scaling
c) Corrosion of metal fixtures
, d) Eye irritation
Correct answer: b) Cloudy water and scaling
Explanation: High alkalinity leads to high pH, causing calcium carbonate to
precipitate, resulting in cloudy water and scale formation.
8. A sudden drop in pool water clarity could indicate:
a) Low cyanuric acid
b) High total dissolved solids
c) Insufficient filtration or improper chemistry
d) Excessive alkalinity
Correct answer: c) Insufficient filtration or improper chemistry
Explanation: Poor clarity often stems from inadequate filtration, poor circulation,
or improper chemical balance (e.g., algae growth, particulate matter).
9. The main purpose of a pool’s main drain is to:
a) Provide a suction outlet for circulation and draining
b) Act as the primary skimming device
c) Add fresh water to the pool
d) Dispense chemicals evenly
Correct answer: a) Provide a suction outlet for circulation and draining
Explanation: The main drain aids water circulation, helps with pool draining, and
prevents stagnation at the bottom.
10. What is the recommended free chlorine residual for a public pool?
a) 0.5–1.0 ppm
b) 1.0–3.0 ppm
c) 3.0–5.0 ppm
d) 5.0–10.0 ppm
Correct answer: b) 1.0–3.0 ppm
Explanation: Maintaining 1–3 ppm free chlorine ensures effective disinfection
while minimizing irritation to swimmers.
11. When backwashing a sand filter, the waste water should be disposed of:
a) Into the storm drain
, b) Into the sanitary sewer (if permitted)
c) Onto nearby landscaping
d) Into a drinking water supply
Correct answer: b) Into the sanitary sewer (if permitted)
Explanation: Backwash water contains contaminants and chemicals; local
regulations typically require disposal into the sanitary sewer to prevent
environmental harm.
12. Which of the following best describes “breakpoint chlorination”?
a) Adding chlorine until combined chlorine is oxidized
b) The point where chlorine demand stops
c) The minimum chlorine needed daily
d) The chlorine level required to kill algae
Correct answer: a) Adding chlorine until combined chlorine is oxidized
Explanation: Breakpoint chlorination involves adding enough chlorine to oxidize
chloramines and organic contaminants, restoring a free chlorine residual.
13. The Langelier Saturation Index measures:
a) Chlorine effectiveness
b) Water balance (tendency to scale or corrode)
c) Total dissolved solids
d) Bacteria count
Correct answer: b) Water balance (tendency to scale or corrode)
Explanation: The index calculates whether water is scale-forming (positive index)
or corrosive (negative index) based on pH, temperature, alkalinity, calcium
hardness, and TDS.
14. A pool pump that is losing prime may be caused by:
a) A clogged skimmer basket
b) High chlorine levels
c) Low total alkalinity
d) High calcium hardness
Correct answer: a) A clogged skimmer basket
Questions and Answers | 2026 Update |
100% Correct
1. The primary purpose of a skimmer in a swimming pool is to:
a) Add chlorine to the water
b) Remove debris from the water surface
c) Circulate water through the filter
d) Heat the pool water
Correct answer: b) Remove debris from the water surface
Explanation: Skimmers draw water from the surface, catching leaves, oils, and
other floating debris before they sink.
2. Which chemical is commonly used to increase the pH level in pool water?
a) Muriatic acid
b) Sodium bicarbonate
c) Sodium hypochlorite
d) Calcium chloride
Correct answer: b) Sodium bicarbonate
Explanation: Sodium bicarbonate (baking soda) raises pH with minimal effect on
alkalinity, unlike sodium carbonate which raises both more significantly.
3. The turnover rate for a public swimming pool is defined as:
a) The time required to filter the entire volume of water
b) The rate at which swimmers enter and exit the pool
c) The frequency of backwashing the filter
d) The rate of chemical addition
Correct answer: a) The time required to filter the entire volume of water
, Explanation: Turnover rate ensures all pool water passes through the filtration
system within a specified time to maintain clarity and hygiene.
4. Combined chlorine in a pool refers to:
a) Free chlorine only
b) Chlorine that has reacted with contaminants
c) The total of calcium and chlorine
d) Chlorine bound to cyanuric acid
Correct answer: b) Chlorine that has reacted with contaminants
Explanation: Combined chlorine is chlorine that has combined with ammonia or
nitrogen compounds, forming chloramines, which cause eye irritation and odor.
5. What is the ideal range for pH in a swimming pool?
a) 6.0–6.8
b) 7.2–7.8
c) 8.0–8.5
d) 5.5–6.5
Correct answer: b) 7.2–7.8
Explanation: pH within 7.2–7.8 ensures bather comfort, optimal chlorine
effectiveness, and prevents corrosion or scaling.
6. Cyanuric acid in pool water serves to:
a) Increase pH
b) Stabilize chlorine from sunlight degradation
c) Prevent calcium scaling
d) Remove metals
Correct answer: b) Stabilize chlorine from sunlight degradation
Explanation: Cyanuric acid acts as a stabilizer, protecting free chlorine from rapid
loss due to ultraviolet rays.
7. Which of the following is a symptom of high total alkalinity?
a) Rapid pH fluctuations
b) Cloudy water and scaling
c) Corrosion of metal fixtures
, d) Eye irritation
Correct answer: b) Cloudy water and scaling
Explanation: High alkalinity leads to high pH, causing calcium carbonate to
precipitate, resulting in cloudy water and scale formation.
8. A sudden drop in pool water clarity could indicate:
a) Low cyanuric acid
b) High total dissolved solids
c) Insufficient filtration or improper chemistry
d) Excessive alkalinity
Correct answer: c) Insufficient filtration or improper chemistry
Explanation: Poor clarity often stems from inadequate filtration, poor circulation,
or improper chemical balance (e.g., algae growth, particulate matter).
9. The main purpose of a pool’s main drain is to:
a) Provide a suction outlet for circulation and draining
b) Act as the primary skimming device
c) Add fresh water to the pool
d) Dispense chemicals evenly
Correct answer: a) Provide a suction outlet for circulation and draining
Explanation: The main drain aids water circulation, helps with pool draining, and
prevents stagnation at the bottom.
10. What is the recommended free chlorine residual for a public pool?
a) 0.5–1.0 ppm
b) 1.0–3.0 ppm
c) 3.0–5.0 ppm
d) 5.0–10.0 ppm
Correct answer: b) 1.0–3.0 ppm
Explanation: Maintaining 1–3 ppm free chlorine ensures effective disinfection
while minimizing irritation to swimmers.
11. When backwashing a sand filter, the waste water should be disposed of:
a) Into the storm drain
, b) Into the sanitary sewer (if permitted)
c) Onto nearby landscaping
d) Into a drinking water supply
Correct answer: b) Into the sanitary sewer (if permitted)
Explanation: Backwash water contains contaminants and chemicals; local
regulations typically require disposal into the sanitary sewer to prevent
environmental harm.
12. Which of the following best describes “breakpoint chlorination”?
a) Adding chlorine until combined chlorine is oxidized
b) The point where chlorine demand stops
c) The minimum chlorine needed daily
d) The chlorine level required to kill algae
Correct answer: a) Adding chlorine until combined chlorine is oxidized
Explanation: Breakpoint chlorination involves adding enough chlorine to oxidize
chloramines and organic contaminants, restoring a free chlorine residual.
13. The Langelier Saturation Index measures:
a) Chlorine effectiveness
b) Water balance (tendency to scale or corrode)
c) Total dissolved solids
d) Bacteria count
Correct answer: b) Water balance (tendency to scale or corrode)
Explanation: The index calculates whether water is scale-forming (positive index)
or corrosive (negative index) based on pH, temperature, alkalinity, calcium
hardness, and TDS.
14. A pool pump that is losing prime may be caused by:
a) A clogged skimmer basket
b) High chlorine levels
c) Low total alkalinity
d) High calcium hardness
Correct answer: a) A clogged skimmer basket
