1|Page
CPO – Certified Pool & Spa Operator Exam 2025/2026 – Verified
Question Bank with 100% Correct Answers
Breakpoint Chlorination - CORRECT ANSWER=eliminate inorganic material,
add enough chlorine free chlorine to destroy chloramines
Calcium Hardness - CORRECT ANSWER=calcium part of the total hardness
reading
Chloramines - CORRECT ANSWER=Combined Chlorine, forms when chlorine
bonds to ammonia, irritant to eyes and skin, strong smell
DE Filter Media - CORRECT ANSWER=white powder, fossilized skeletons, used
in DE Filters
Effluent - CORRECT ANSWER=outflow of water from pump, filter, pool
Electrode/Probe - CORRECT ANSWER=measures water properties
Erosion Feeder - CORRECT ANSWER=chemical feed device, water passes
through and erodes the dry chemical
Free Chlorine - CORRECT ANSWER=available chlorine, reacts to DPR powder
for testing
Hydrochloric Acid (HCL) - CORRECT ANSWER=Also called Muriatic Acid,
strong acid used to reduce pH and Total Alkalinity
, 2|Page
Influent - CORRECT ANSWER=in flow of water to a pump, filter, pool
Oxidation Reduction Potential (ORP) - CORRECT ANSWER=measures how
effective the chlorine is in the water, relates to the concentration of oxidizer
Parts Per Million (PPM) - CORRECT ANSWER=measured in 1 million units
pH - CORRECT ANSWER=logarithm of the hydrogen-ion in the water
Saturation Index - CORRECT ANSWER=calculation to predict if water has a
tendency to be corrosive
Sodium Hypochlorite (NaOCl) - CORRECT ANSWER=Liquid bleach, liquid
chlorine, disenfectant, 10-15% available chlorine for pools, 5% for household use
Sodium Carbonate (Na2CO3) - CORRECT ANSWER=white powder, raise pH
and alkalinity
Sodium Thiosulfate (Na2S2O3) - CORRECT ANSWER=used to remove chlorine
from water
Superchlorination - CORRECT ANSWER=adding large amount of chlorine to
water to destroy
CPO – Certified Pool & Spa Operator Exam 2025/2026 – Verified
Question Bank with 100% Correct Answers
Breakpoint Chlorination - CORRECT ANSWER=eliminate inorganic material,
add enough chlorine free chlorine to destroy chloramines
Calcium Hardness - CORRECT ANSWER=calcium part of the total hardness
reading
Chloramines - CORRECT ANSWER=Combined Chlorine, forms when chlorine
bonds to ammonia, irritant to eyes and skin, strong smell
DE Filter Media - CORRECT ANSWER=white powder, fossilized skeletons, used
in DE Filters
Effluent - CORRECT ANSWER=outflow of water from pump, filter, pool
Electrode/Probe - CORRECT ANSWER=measures water properties
Erosion Feeder - CORRECT ANSWER=chemical feed device, water passes
through and erodes the dry chemical
Free Chlorine - CORRECT ANSWER=available chlorine, reacts to DPR powder
for testing
Hydrochloric Acid (HCL) - CORRECT ANSWER=Also called Muriatic Acid,
strong acid used to reduce pH and Total Alkalinity
, 2|Page
Influent - CORRECT ANSWER=in flow of water to a pump, filter, pool
Oxidation Reduction Potential (ORP) - CORRECT ANSWER=measures how
effective the chlorine is in the water, relates to the concentration of oxidizer
Parts Per Million (PPM) - CORRECT ANSWER=measured in 1 million units
pH - CORRECT ANSWER=logarithm of the hydrogen-ion in the water
Saturation Index - CORRECT ANSWER=calculation to predict if water has a
tendency to be corrosive
Sodium Hypochlorite (NaOCl) - CORRECT ANSWER=Liquid bleach, liquid
chlorine, disenfectant, 10-15% available chlorine for pools, 5% for household use
Sodium Carbonate (Na2CO3) - CORRECT ANSWER=white powder, raise pH
and alkalinity
Sodium Thiosulfate (Na2S2O3) - CORRECT ANSWER=used to remove chlorine
from water
Superchlorination - CORRECT ANSWER=adding large amount of chlorine to
water to destroy
