CPO EXAM 24|2025 | ACTUAL EXAM ,
QUESTIONS AND ANSWERS | GRADED A+
reducing hazards - prevention is the best option
water contamination - 1. fecal related (crypto, giardia, shigella, e coli, adenovirus,
hepatitis A)
2. non-fecal (pseudomonas aeruginosa, swimmer's ear, legionella pneumophila,
molluspioxvirus, planter's warts, athlete's foot)
CDC - Center for Disease Control Prevention
solid fecal incident - remove people, pH between 7.2-7.5, raise chlorine 2.0 ppm, 30
minute break
diarrhea - remove people, pH 7.2-7.5, raise chlorine to 20.0 ppm (12.75 hrs), after
backwash filters, raise chlorine to normal, then re-open pool
handling contaminated material - wear gloves, remove excess, disinfect all surfaces,
follow guidelines of disposal & wash hands
prevention practices - 1. maintain proper disinfectant levels at all times
2. have kids use bathroom before
3. swimmer's shower before swimming
4. prohibit swimming with wounds/sores
5. work with local health department
disinfection - aka sanitation=destroying microorganisms; consider chemical safety &
storage space when considering a disinfectant
oxidation - process of changing a chemical structure of contaminants to remove from
water (turn into simple gases); affected by: pH, temperature, environmental wastes &
bather contamination
what is the most common disinfectant used - chlorine
chlorine compounds - 1. organic (trichlor and dichlor); contain cyanuric acid; stabilized
2. inorganic (calcium hypochlorite, sodium hypochlorite, lithium hypochlorite, chlorine
gas); no cyanuric acid; unstabalized, but can be stabilized with acid; sensitive to light
, cyanuric acid - 30-50 ppm; decreases breakdown of chlorine because UV radiation
(10x as strong)
chemistry of chlorine - when a chlorine compound is introduced to water this leads to a
chemical reaction which creates either hypochlorous acid (kills microorganisms) or
hypochlorite ion (inactive form of chlorine)
types of chlorine - free (available for disinfection), combined, or total
DPD tests - measure of free chlorine; kits or strip tests; see different shades of reds
acceptable range of free chlorine - 1.0-5.0ppm
combined chlorine (chloramines) - free chlorine plus ammonia or nitrogen containing
organic compounds (chemical bond); no longer an effective disinfectant (may cause
odor, etc.); ideal amount should be 0 (allowed amount= 0.2 ppm in pools or 0.5 ppm in
spas)
bromine - disinfectant in pools/spas-good algicidal properties--not as good oxidizer--
tablets or sodium bromine
ozone - disinfectant in pools/spas; must be used with chlorine or bromine; can't be
transported; leaves no residue in water; produced by ultra violet light or corona
discharge
water balance - correct ratio of mineral content and pH to prevent pool water from
being corrosive/scaly; protects pool from chemical erosion
factors that contribute to water balance - pH, alkalinity, calcium hardness, temperature,
total dissolved solids
pH - proteins hydrogen; most impact on balanced water; measured by acid vs. base: 0-
14 (0=acidic, 14=base, 7=neutral); 6 has 10x the pH of 7, 7 has 10x the pH of 8, etc.
pool pH - should be slightly above neutral; most compatible range=7.2 and 7.8;
ideal=7.4 and 7.6; lower the pH, the more effective
total alkalinity - measure of ability of water to resist changes in pH (w/o can have
dramatic high and lows); prevent pH bounce; acceptable range=60 to 180 ppm/ ideal
range=80 to 120ppm
low total alkalinity - from pH fluctuation & may need to ne adjusted if cyanuric
acid(CYA) is present; high TA=hard to make chemical change
to adjust TA - TA-(CYA/3)
QUESTIONS AND ANSWERS | GRADED A+
reducing hazards - prevention is the best option
water contamination - 1. fecal related (crypto, giardia, shigella, e coli, adenovirus,
hepatitis A)
2. non-fecal (pseudomonas aeruginosa, swimmer's ear, legionella pneumophila,
molluspioxvirus, planter's warts, athlete's foot)
CDC - Center for Disease Control Prevention
solid fecal incident - remove people, pH between 7.2-7.5, raise chlorine 2.0 ppm, 30
minute break
diarrhea - remove people, pH 7.2-7.5, raise chlorine to 20.0 ppm (12.75 hrs), after
backwash filters, raise chlorine to normal, then re-open pool
handling contaminated material - wear gloves, remove excess, disinfect all surfaces,
follow guidelines of disposal & wash hands
prevention practices - 1. maintain proper disinfectant levels at all times
2. have kids use bathroom before
3. swimmer's shower before swimming
4. prohibit swimming with wounds/sores
5. work with local health department
disinfection - aka sanitation=destroying microorganisms; consider chemical safety &
storage space when considering a disinfectant
oxidation - process of changing a chemical structure of contaminants to remove from
water (turn into simple gases); affected by: pH, temperature, environmental wastes &
bather contamination
what is the most common disinfectant used - chlorine
chlorine compounds - 1. organic (trichlor and dichlor); contain cyanuric acid; stabilized
2. inorganic (calcium hypochlorite, sodium hypochlorite, lithium hypochlorite, chlorine
gas); no cyanuric acid; unstabalized, but can be stabilized with acid; sensitive to light
, cyanuric acid - 30-50 ppm; decreases breakdown of chlorine because UV radiation
(10x as strong)
chemistry of chlorine - when a chlorine compound is introduced to water this leads to a
chemical reaction which creates either hypochlorous acid (kills microorganisms) or
hypochlorite ion (inactive form of chlorine)
types of chlorine - free (available for disinfection), combined, or total
DPD tests - measure of free chlorine; kits or strip tests; see different shades of reds
acceptable range of free chlorine - 1.0-5.0ppm
combined chlorine (chloramines) - free chlorine plus ammonia or nitrogen containing
organic compounds (chemical bond); no longer an effective disinfectant (may cause
odor, etc.); ideal amount should be 0 (allowed amount= 0.2 ppm in pools or 0.5 ppm in
spas)
bromine - disinfectant in pools/spas-good algicidal properties--not as good oxidizer--
tablets or sodium bromine
ozone - disinfectant in pools/spas; must be used with chlorine or bromine; can't be
transported; leaves no residue in water; produced by ultra violet light or corona
discharge
water balance - correct ratio of mineral content and pH to prevent pool water from
being corrosive/scaly; protects pool from chemical erosion
factors that contribute to water balance - pH, alkalinity, calcium hardness, temperature,
total dissolved solids
pH - proteins hydrogen; most impact on balanced water; measured by acid vs. base: 0-
14 (0=acidic, 14=base, 7=neutral); 6 has 10x the pH of 7, 7 has 10x the pH of 8, etc.
pool pH - should be slightly above neutral; most compatible range=7.2 and 7.8;
ideal=7.4 and 7.6; lower the pH, the more effective
total alkalinity - measure of ability of water to resist changes in pH (w/o can have
dramatic high and lows); prevent pH bounce; acceptable range=60 to 180 ppm/ ideal
range=80 to 120ppm
low total alkalinity - from pH fluctuation & may need to ne adjusted if cyanuric
acid(CYA) is present; high TA=hard to make chemical change
to adjust TA - TA-(CYA/3)
