CPO EXAM GUIDE QUESTIONS WITH
COMPLETE SOLUTION
p 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)
calcium hardness - low=corrosive water/high=scaling water; can be raised by using a calcium chloride or
calcium hypochlorite as a disinfectant; to lower: drain or dilute water; acceptable level=150/ ideal=200
to 400ppm
temperature - physical effect; affects solubility of chemicals; most soluble as temperature rises; calcium
more soluble as temperature falls
higher temperatures - scaling conditions
lower temperatures - corrosive conditions
total dissolved solids (TDS) - all minerals dissolved in water ("age");
"old" water has more contaminants than "new"; may effect solubility or effectiveness of disinfectants
Langelier saturation index (SI) - determines if water is corrosive, scale forming or balanced; pH + temp +
calcium hardness + TA - TDS (if in between, go to next highest value)
COMPLETE SOLUTION
p 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)
calcium hardness - low=corrosive water/high=scaling water; can be raised by using a calcium chloride or
calcium hypochlorite as a disinfectant; to lower: drain or dilute water; acceptable level=150/ ideal=200
to 400ppm
temperature - physical effect; affects solubility of chemicals; most soluble as temperature rises; calcium
more soluble as temperature falls
higher temperatures - scaling conditions
lower temperatures - corrosive conditions
total dissolved solids (TDS) - all minerals dissolved in water ("age");
"old" water has more contaminants than "new"; may effect solubility or effectiveness of disinfectants
Langelier saturation index (SI) - determines if water is corrosive, scale forming or balanced; pH + temp +
calcium hardness + TA - TDS (if in between, go to next highest value)
