CPO Exam Guide Questions and
Answers Latest Versions 2025 Top
Rated A+
2. adding chemicals manually: 1. close pool
2. add downstream
3. don't add water to chemicals; AAA=always add acid
4. never mix chemicals
5. material safety data sheets (MSDS) must be understood & kept on sight
3. chemical testing: based on when should be performed, frequency & what
method; helps prevent incidents & required by law/health codes; improper testing
can lead to numerous harmful incidents
4. 4 basic chemical testing methods: 1. colorimetric (color matching; test chlo-
rine ppm, disinfection & pH)
2. titrimetric (disinfection, TA, calcium hardness; more accurate)
3. turbidmetric (cyanuric acid, water clarity; light rays shinning through water)
4. electronic (TDS, pH , temp, oxidation reduction potential; electronic problems;
,most accurate)
5. oxidation reduction potential (redox): measure of the oxidizing capacity
present in water; measured in millivolts (MV); uses probes (indirect measure of
disinfectant level), most disinfectants are oxidizers--increases as oxidizer concen-
tration increases; probes must be cleaned monthly
6. test kits must be taken care of: out of sunlight, between 36F & 85F, do not
expose to chemical fumes, etc.
7. collecting water samples: follow instructions, never use glass or metallic, take
at least 18 inches from below surface
8. turnover rate: amount of time needed to circulate volume of the pool one
time--measured in hours;
pool=6hrs
waterpark & specialty=1-2hrs
wading pool=1-2hrs
spas=0.5hrs (30min)
9. flow rate: amount of water passing through the circulation system at a given
time--gallons per minute (gpm)
10. factors influencing circulation: inlet placement & design, pool shape & con-
tour, surface & main water drain removal, circulation pumps, piping & fittings
11. acceptable range of free chlorine: 1.0-5.0ppm
12. 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)
13. bromine: disinfectant in pools/spas-good algicidal properties--not as good
oxidizer--tablets or sodium bromine
14. 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
15. water balance: correct ratio of mineral content and pH to prevent pool water
from being corrosive/scaly; protects pool from chemical erosion
16. factors that contribute to water balance: pH, alkalinity, calcium hardness,
temperature, total dissolved solids
17. 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.
18. 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
19. 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
20. low total alkalinity: from pH fluctuation & may need to ne adjusted if cyanuric
acid(CYA) is present; high TA=hard to make chemical change
21. to adjust TA: TA-(CYA/3)
22. calcium hardness: low=corrosive water/high=scaling water; can be raised by
Answers Latest Versions 2025 Top
Rated A+
2. adding chemicals manually: 1. close pool
2. add downstream
3. don't add water to chemicals; AAA=always add acid
4. never mix chemicals
5. material safety data sheets (MSDS) must be understood & kept on sight
3. chemical testing: based on when should be performed, frequency & what
method; helps prevent incidents & required by law/health codes; improper testing
can lead to numerous harmful incidents
4. 4 basic chemical testing methods: 1. colorimetric (color matching; test chlo-
rine ppm, disinfection & pH)
2. titrimetric (disinfection, TA, calcium hardness; more accurate)
3. turbidmetric (cyanuric acid, water clarity; light rays shinning through water)
4. electronic (TDS, pH , temp, oxidation reduction potential; electronic problems;
,most accurate)
5. oxidation reduction potential (redox): measure of the oxidizing capacity
present in water; measured in millivolts (MV); uses probes (indirect measure of
disinfectant level), most disinfectants are oxidizers--increases as oxidizer concen-
tration increases; probes must be cleaned monthly
6. test kits must be taken care of: out of sunlight, between 36F & 85F, do not
expose to chemical fumes, etc.
7. collecting water samples: follow instructions, never use glass or metallic, take
at least 18 inches from below surface
8. turnover rate: amount of time needed to circulate volume of the pool one
time--measured in hours;
pool=6hrs
waterpark & specialty=1-2hrs
wading pool=1-2hrs
spas=0.5hrs (30min)
9. flow rate: amount of water passing through the circulation system at a given
time--gallons per minute (gpm)
10. factors influencing circulation: inlet placement & design, pool shape & con-
tour, surface & main water drain removal, circulation pumps, piping & fittings
11. acceptable range of free chlorine: 1.0-5.0ppm
12. 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)
13. bromine: disinfectant in pools/spas-good algicidal properties--not as good
oxidizer--tablets or sodium bromine
14. 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
15. water balance: correct ratio of mineral content and pH to prevent pool water
from being corrosive/scaly; protects pool from chemical erosion
16. factors that contribute to water balance: pH, alkalinity, calcium hardness,
temperature, total dissolved solids
17. 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.
18. 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
19. 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
20. low total alkalinity: from pH fluctuation & may need to ne adjusted if cyanuric
acid(CYA) is present; high TA=hard to make chemical change
21. to adjust TA: TA-(CYA/3)
22. calcium hardness: low=corrosive water/high=scaling water; can be raised by
