LATEST CERTIFIED POOL OPERATOR
PRACTICE QUESTIONS AND ANSWERS
2026/2027
The percentage of hypoclorous acid formation is most influenced by: - ANSWER-pH
Pool painting is usually done: - ANSWER-Before opening in the spring
When a pool is chlorinated with gas chlorine, the operator must also use: - ANSWER-
Soda Ash
The term "chlorine demand" refers to: - ANSWER-The amount of chlorine which will
react with substances in the pool
Re-circulation pumps used in swimming pools are the type called: - ANSWER-
Centrifugal pumps
Reversing the flow of water through the filters is called: - ANSWER-Backwash
"Slurry feed" or "body feed" refers to: - ANSWER-Diatomite added during a filter run
The term pH is determined by the concentration of: - ANSWER-Hydrogen ions
Because carbonate ions combine with hydrogen ions, sodium carbonate will cause pH
to: - ANSWER-Rise
When enough chlorine is added to cause complete oxidation of all organic compounds,
a sudden drop in residual chlorine may be noticed. The point at which this occurs is
called the: - ANSWER-Break-point
"Residual chlorine" refers to: - ANSWER-The amount left in the water after oxidation of
organic material
Which of the following is NOT considered a swimming pool disinfectant: - ANSWER-
Chlorinated hydrocarbons
When chlorine is used as a disinfectant for swimming pools, the form in which it's
disinfectant properties are the greatest is: - ANSWER-Hypochlorous acid
The chemical most commonly used to raise pH is: - ANSWER-Sodium carbonate
An example of a chemical used to stabilize chlorine is: - ANSWER-Cyanuric acid
, The chemical reagent recommended by the health department to test chlorine residual
in swimming pools is: - ANSWER-D.P.D.
The chemical reagent used most often to test pH in swimming pools is: - ANSWER-
Phenol red
Considering all factors, which of the following would be the BEST range for pH in a
swimming pool: - ANSWER-7.2-7.8
The minimum turnover rate to obtain 100% clarity in a pool is: - ANSWER-Once in eight
hours
There is a noticeable odor of chlorine around your pool and bathers are complaining of
eye irritation. Which of the following is most likely to solve the problem: - ANSWER-
Break point chlorination
As pH increases, chlorine effectiveness: - ANSWER-Decreases
In a high-rate sand filter system, the tanks are backwashed: - ANSWER-All at once
The baffle in the filter tank is there to: - ANSWER-Disperse water evenly over the
surface of the filter media
An access manhole is constructed on each tank in sand and anthracite filter systems: -
ANSWER-All of the above
A hair and lint strainer should be located: - ANSWER-Before the pump and before the
filter
Sodium hypochlorite used as a pool sanitizer also affects the water pH in the following
manner: - ANSWER-Raises
Chlorine gas will ________ the pH: - ANSWER-Lower
DE systems should be turned off for a "rest": - ANSWER-Never
If the filter run is started with clean filters, the difference between the influent and
effluent gauges should be: - ANSWER-Very little
Glass containers are: - ANSWER-Never allowed in the pool enclosure
Which of the following factors would produce a greater consumption of disinfectant in a
pool: - ANSWER-Bather load plus sunlight
In a stabilized pool, the concentration of cyanuric acid should not exceed: - ANSWER-
100 ppm
PRACTICE QUESTIONS AND ANSWERS
2026/2027
The percentage of hypoclorous acid formation is most influenced by: - ANSWER-pH
Pool painting is usually done: - ANSWER-Before opening in the spring
When a pool is chlorinated with gas chlorine, the operator must also use: - ANSWER-
Soda Ash
The term "chlorine demand" refers to: - ANSWER-The amount of chlorine which will
react with substances in the pool
Re-circulation pumps used in swimming pools are the type called: - ANSWER-
Centrifugal pumps
Reversing the flow of water through the filters is called: - ANSWER-Backwash
"Slurry feed" or "body feed" refers to: - ANSWER-Diatomite added during a filter run
The term pH is determined by the concentration of: - ANSWER-Hydrogen ions
Because carbonate ions combine with hydrogen ions, sodium carbonate will cause pH
to: - ANSWER-Rise
When enough chlorine is added to cause complete oxidation of all organic compounds,
a sudden drop in residual chlorine may be noticed. The point at which this occurs is
called the: - ANSWER-Break-point
"Residual chlorine" refers to: - ANSWER-The amount left in the water after oxidation of
organic material
Which of the following is NOT considered a swimming pool disinfectant: - ANSWER-
Chlorinated hydrocarbons
When chlorine is used as a disinfectant for swimming pools, the form in which it's
disinfectant properties are the greatest is: - ANSWER-Hypochlorous acid
The chemical most commonly used to raise pH is: - ANSWER-Sodium carbonate
An example of a chemical used to stabilize chlorine is: - ANSWER-Cyanuric acid
, The chemical reagent recommended by the health department to test chlorine residual
in swimming pools is: - ANSWER-D.P.D.
The chemical reagent used most often to test pH in swimming pools is: - ANSWER-
Phenol red
Considering all factors, which of the following would be the BEST range for pH in a
swimming pool: - ANSWER-7.2-7.8
The minimum turnover rate to obtain 100% clarity in a pool is: - ANSWER-Once in eight
hours
There is a noticeable odor of chlorine around your pool and bathers are complaining of
eye irritation. Which of the following is most likely to solve the problem: - ANSWER-
Break point chlorination
As pH increases, chlorine effectiveness: - ANSWER-Decreases
In a high-rate sand filter system, the tanks are backwashed: - ANSWER-All at once
The baffle in the filter tank is there to: - ANSWER-Disperse water evenly over the
surface of the filter media
An access manhole is constructed on each tank in sand and anthracite filter systems: -
ANSWER-All of the above
A hair and lint strainer should be located: - ANSWER-Before the pump and before the
filter
Sodium hypochlorite used as a pool sanitizer also affects the water pH in the following
manner: - ANSWER-Raises
Chlorine gas will ________ the pH: - ANSWER-Lower
DE systems should be turned off for a "rest": - ANSWER-Never
If the filter run is started with clean filters, the difference between the influent and
effluent gauges should be: - ANSWER-Very little
Glass containers are: - ANSWER-Never allowed in the pool enclosure
Which of the following factors would produce a greater consumption of disinfectant in a
pool: - ANSWER-Bather load plus sunlight
In a stabilized pool, the concentration of cyanuric acid should not exceed: - ANSWER-
100 ppm
