Certified Pool Operator (CPO) Test Review
2025/2026 | Complete Study Guide
12 Reasons why the health inspector will close your pool - correct answer1. pump filter
not working for more than an hour
2. main drain is not visible
3. chemical readings out of range
4. no pool operator (15 minute grace period)
5. no lifeguard or cpr certs present
6. water is below the skimmer line
7. danger to the public
8. chlorinator is not working
9. health inspector is not allowed in
10. bathrooms + drains not working
11. flow rate is too low
12. no phone (landline)
Measuring records as the CPO - correct answerOperator must test the water for Cl and
pH every hour, and Total Alkalinity, Calcium Hardness and Cyanuric Acid once per
week. Records must be maintained on site and available for at least 2 years at the pool
and 3 years total.
5 Factors of Water Balance - correct answerpH, Total Alkalinity, Calcium Hardness,
Temperature, and total dissolved liquids
Corrosive water - correct answerpH is too low, dissolves everything it contacts
scaling water - correct answerpH it too high, mineral deposits on walls or pipes
Regulated pH range - correct answer7.2-7.8
pH reading is tested with Phenol Red
To lower pH, - correct answeradd muriatic acid
To raise the pH, - correct answeradd sodium carbonate (Soda Ash)
2. sodium bisulfate
3. carbon dioxide
Total Alkalinity - correct answerrepresents the amount of carbonates, bicarbonates, and
hydroxides in a solution - you want this to be high, because the pH resists changes in
fluctuating
, pH Bounce - correct answerlow alkalinity
Regulated Total Alkalinity range - correct answer60-180 ppm ideal goal is 100ppm
To lower Total Alkalinity, - correct answeradd muriatic acid
To raise Total Alkalinity, - correct answeradd Baking Soda
Calcium Hardness - correct answeramount of calcium and magnesium in the water
(mineral content in water)
Regulated calcium hardness range - correct answer150-400ppm
To raise Calcium Hardness, - correct answeradd calcium chloride
Total Dissolved Liquids (TDS) - correct answersum of all organic and inorganic
materials dissolved in the water- cannot be eliminated with a chemical----- <1500 ppm
allowed in water
Temperature - correct answerMax temps = 88 for swimming pool
96 for therapy pool
104 for hot tub
Saturation Index - correct answer-.5-.5
check once a week for a pool, everyday for a spa
Employees have the right to know: - correct answer- may come into contact w/blood
-may come into contact w/ dangerous chemicals
- personal protection
- material safety data sheet
Cyanuric Acid (CYA) - correct answerchemical used to stabilize an outdoor pool (not UV
light sensitive) added directly through the skimmer,
Regulated Cya levels - correct answer30-100 ppm
Sodium Hypochlorite NaOCl - correct answerLiquid Chlorine, or bleach
Chlorine Breakdown
FAC's and CAC's - correct answerFree Available Chlorine = good chlorine (disinfects)
Combined Available Chlorine = Chloramines = bad stuff you can smell, ammonia and
no disinfectants
Regulated range for FAC's - correct answer1.5-10 for a pool
3-10 for a wading pool
2025/2026 | Complete Study Guide
12 Reasons why the health inspector will close your pool - correct answer1. pump filter
not working for more than an hour
2. main drain is not visible
3. chemical readings out of range
4. no pool operator (15 minute grace period)
5. no lifeguard or cpr certs present
6. water is below the skimmer line
7. danger to the public
8. chlorinator is not working
9. health inspector is not allowed in
10. bathrooms + drains not working
11. flow rate is too low
12. no phone (landline)
Measuring records as the CPO - correct answerOperator must test the water for Cl and
pH every hour, and Total Alkalinity, Calcium Hardness and Cyanuric Acid once per
week. Records must be maintained on site and available for at least 2 years at the pool
and 3 years total.
5 Factors of Water Balance - correct answerpH, Total Alkalinity, Calcium Hardness,
Temperature, and total dissolved liquids
Corrosive water - correct answerpH is too low, dissolves everything it contacts
scaling water - correct answerpH it too high, mineral deposits on walls or pipes
Regulated pH range - correct answer7.2-7.8
pH reading is tested with Phenol Red
To lower pH, - correct answeradd muriatic acid
To raise the pH, - correct answeradd sodium carbonate (Soda Ash)
2. sodium bisulfate
3. carbon dioxide
Total Alkalinity - correct answerrepresents the amount of carbonates, bicarbonates, and
hydroxides in a solution - you want this to be high, because the pH resists changes in
fluctuating
, pH Bounce - correct answerlow alkalinity
Regulated Total Alkalinity range - correct answer60-180 ppm ideal goal is 100ppm
To lower Total Alkalinity, - correct answeradd muriatic acid
To raise Total Alkalinity, - correct answeradd Baking Soda
Calcium Hardness - correct answeramount of calcium and magnesium in the water
(mineral content in water)
Regulated calcium hardness range - correct answer150-400ppm
To raise Calcium Hardness, - correct answeradd calcium chloride
Total Dissolved Liquids (TDS) - correct answersum of all organic and inorganic
materials dissolved in the water- cannot be eliminated with a chemical----- <1500 ppm
allowed in water
Temperature - correct answerMax temps = 88 for swimming pool
96 for therapy pool
104 for hot tub
Saturation Index - correct answer-.5-.5
check once a week for a pool, everyday for a spa
Employees have the right to know: - correct answer- may come into contact w/blood
-may come into contact w/ dangerous chemicals
- personal protection
- material safety data sheet
Cyanuric Acid (CYA) - correct answerchemical used to stabilize an outdoor pool (not UV
light sensitive) added directly through the skimmer,
Regulated Cya levels - correct answer30-100 ppm
Sodium Hypochlorite NaOCl - correct answerLiquid Chlorine, or bleach
Chlorine Breakdown
FAC's and CAC's - correct answerFree Available Chlorine = good chlorine (disinfects)
Combined Available Chlorine = Chloramines = bad stuff you can smell, ammonia and
no disinfectants
Regulated range for FAC's - correct answer1.5-10 for a pool
3-10 for a wading pool
