REHS Practice Test Exam With Correct
Questions And Answers 2025
Soil permeability procedure involves evaluating a soil core or test pit. What does the
procedure yield?
a. Permeability estimated seepage rate
b. Permeability estimated application rate
c. Permeability estimated range - CORRECT ANSWERS-b. Permeability estimate
How does chlorine kill microorganisms and bacteria?
a. By weakening enzymes and destroying internal organelles
b. By attacking lipids in cell walls and destroying enzymes and structures inside
c. By breaking bonds and poisoning the cell - CORRECT ANSWERS-b. By attacking
lipids in cell walls and destroying enzymes and structures inside
When chlorine is added to water, what is formed?
a. Hypochlorous acid and hypochlorite ion
b. Hypochlorite acid and hypochlorite ion
c. Hypochloric acid and hypochlorite ion - CORRECT ANSWERS-a. Hypochlorous acid
and hypochlorite ion
What two acids are formed when you add liquefied chlorine gas (Cl2) to water?
a. Hypochlorite acid and hydrochloric acid
b. Hypochlorous acid and hydrochloric acid
c. Hypochloric acid and hydrochloric acid - CORRECT ANSWERS-b. Hypochlorous acid
(HOCL) and hydrochloric acid (HCl)
What cause pH to jump?
a. Low alkalinity, precipitation, algae growth
b. High alkalinity, precipitation, algae growth
c. Low alkalinity, high calcium hardness, algae growth - CORRECT ANSWERS-a. Low
alkalinity, precipitation, algae growth
What do you add to lower pH?
a. Sodium bisulphate (NaHSO4)
b. HCl
c. aerate with CO2
,d. all of the above - CORRECT ANSWERS-d. all of the above
What do you add to raise pH?
a. Sodium carbonate (Na2CO3) (Soda Ash)
b. Sodium bicarbonate
c. Sodium bisulphate - CORRECT ANSWERS-a. Sodium carbonate (Na2CO3) (Soda
Ash)
Why do you use algaecides in pool even though chlorine is used?
a. Chlorine is not effective against algae
b. Chlorine levels required to kill aglae are dangerously high
c. Insurance against sloppy chlorination - CORRECT ANSWERS-c. Insurance against
sloppy chlorination
Ozone (O3) is ______ faster than chlorine:
a. 1500X
b. 2000X
c. 3000X
d. 4000X - CORRECT ANSWERS-c. 3000X
What do you add to raise alkalinity?
a. Sodium bicarbonate (baking soda)
b. Sodium carbonate (soda ash)
c. Sodium bisulphate (sodium hygroden sulfate) - CORRECT ANSWERS-a. Sodium
bicarbonate (baking soda)
What level of TDS reduce chlorine efficiency and cause cloudy water?
a. >1000 ppm yields
b. >1500 ppm yields
c. >2000 ppm yields
d. >2500 ppm yields - CORRECT ANSWERS-b. >1500 yields
What is the solution to high TDS yields?
a. Superchlorination
b. Lower pH
c. Dilution - CORRECT ANSWERS-c. Dilution is the only solution!
How do you eliminate existing algae?
a. Superchlorinate
,b. Copper Sulfate CuSO4
c. Sodium carbonate Na2SO4
d. a and b - CORRECT ANSWERS-d. a and b
Superchlorination is used to combat all of the following, except:
a. Algae
b. pseudomonas aeruginosa
c. Entamoeba histolytica
d. Giardia lamblia
e. Leptospira spp.
f. Cryptosporidium spp.
g Schistosoma spp. - CORRECT ANSWERS-e. Leptospira spp.
How often should a private pool be shocked?
a. Every month, every 2 weeks when hot
b. Every 2 weeks, every week when hot
c. Every week, every 2 days when hot - CORRECT ANSWERS-b. Every 2 weeks, every
week when hot
When is it time to shock a public pool?
a. When combined chlorine > 0.2 ppm
b. When combined chlorine > 0.4 ppm
c. When combined chlorine > 0.6 ppm - CORRECT ANSWERS-a. When combined
chlorine > 0.2 ppm
How much chlorine is needed to shock?
a. Bring water to 2X value for CC
b. Bring water to 5 X value for CC
c. Bring water to 10 X value for CC
d. Bring water to 15 X value for CC - CORRECT ANSWERS-c. Bring water to 10X value
for CC
What kind of shock can be used when superchlorinating a brome pool?
a. Potassium monopersulfate
b. Potassium chloride
c. Potassium iodide - CORRECT ANSWERS-a. Potassium monopersulfate
Why would an operator use bromine sanitizer over chlorine sanitizer?
a. Cheaper
b. Easier to maintain pH
, c. Better residual
d. a and c - CORRECT ANSWERS-d. a and c
What is the ideal range of chlorine in swimming pools?
a. 1.0-4.0
b. 2.0-5.0
c. 3.0-6.0
d. 4.0-7.0 - CORRECT ANSWERS-a. 1.0-4.0
What is the ideal range of bromine in swimming pools?
a. 1.0-3.0
b. 3.0-5.0
c. 5.0-7.0 - CORRECT ANSWERS-b. 3.0-5.0
What is the allowed range of pH in pools?
a. 7.0-7.8
b. 7.0-8.0
c. 7.2-7.8
d. 7.2-8.0 - CORRECT ANSWERS-c. 7.2-7.8
What is the ideal range of alkalinity in pools?
a. 40-100 ppm
b. 60-120 ppm
c. 80-120 ppm
d. 80-140 ppm - CORRECT ANSWERS-c. 80-120 ppm
What is the ideal range of cyanuric acid in pools?
a. 10-100 ppm
b. 30-100 ppm
c. 50-100 ppm - CORRECT ANSWERS-b. 30-100 ppm
What kind of pools can bromine sanitizer NOT be used at?
a. Wading pools
b. Outdoor pools
c. Flume pools - CORRECT ANSWERS-b. Outdoor pools
Brome is easily destroyed by UV
What is the flow rate of DE filters?
a. 2.0 gpm/ft2
Questions And Answers 2025
Soil permeability procedure involves evaluating a soil core or test pit. What does the
procedure yield?
a. Permeability estimated seepage rate
b. Permeability estimated application rate
c. Permeability estimated range - CORRECT ANSWERS-b. Permeability estimate
How does chlorine kill microorganisms and bacteria?
a. By weakening enzymes and destroying internal organelles
b. By attacking lipids in cell walls and destroying enzymes and structures inside
c. By breaking bonds and poisoning the cell - CORRECT ANSWERS-b. By attacking
lipids in cell walls and destroying enzymes and structures inside
When chlorine is added to water, what is formed?
a. Hypochlorous acid and hypochlorite ion
b. Hypochlorite acid and hypochlorite ion
c. Hypochloric acid and hypochlorite ion - CORRECT ANSWERS-a. Hypochlorous acid
and hypochlorite ion
What two acids are formed when you add liquefied chlorine gas (Cl2) to water?
a. Hypochlorite acid and hydrochloric acid
b. Hypochlorous acid and hydrochloric acid
c. Hypochloric acid and hydrochloric acid - CORRECT ANSWERS-b. Hypochlorous acid
(HOCL) and hydrochloric acid (HCl)
What cause pH to jump?
a. Low alkalinity, precipitation, algae growth
b. High alkalinity, precipitation, algae growth
c. Low alkalinity, high calcium hardness, algae growth - CORRECT ANSWERS-a. Low
alkalinity, precipitation, algae growth
What do you add to lower pH?
a. Sodium bisulphate (NaHSO4)
b. HCl
c. aerate with CO2
,d. all of the above - CORRECT ANSWERS-d. all of the above
What do you add to raise pH?
a. Sodium carbonate (Na2CO3) (Soda Ash)
b. Sodium bicarbonate
c. Sodium bisulphate - CORRECT ANSWERS-a. Sodium carbonate (Na2CO3) (Soda
Ash)
Why do you use algaecides in pool even though chlorine is used?
a. Chlorine is not effective against algae
b. Chlorine levels required to kill aglae are dangerously high
c. Insurance against sloppy chlorination - CORRECT ANSWERS-c. Insurance against
sloppy chlorination
Ozone (O3) is ______ faster than chlorine:
a. 1500X
b. 2000X
c. 3000X
d. 4000X - CORRECT ANSWERS-c. 3000X
What do you add to raise alkalinity?
a. Sodium bicarbonate (baking soda)
b. Sodium carbonate (soda ash)
c. Sodium bisulphate (sodium hygroden sulfate) - CORRECT ANSWERS-a. Sodium
bicarbonate (baking soda)
What level of TDS reduce chlorine efficiency and cause cloudy water?
a. >1000 ppm yields
b. >1500 ppm yields
c. >2000 ppm yields
d. >2500 ppm yields - CORRECT ANSWERS-b. >1500 yields
What is the solution to high TDS yields?
a. Superchlorination
b. Lower pH
c. Dilution - CORRECT ANSWERS-c. Dilution is the only solution!
How do you eliminate existing algae?
a. Superchlorinate
,b. Copper Sulfate CuSO4
c. Sodium carbonate Na2SO4
d. a and b - CORRECT ANSWERS-d. a and b
Superchlorination is used to combat all of the following, except:
a. Algae
b. pseudomonas aeruginosa
c. Entamoeba histolytica
d. Giardia lamblia
e. Leptospira spp.
f. Cryptosporidium spp.
g Schistosoma spp. - CORRECT ANSWERS-e. Leptospira spp.
How often should a private pool be shocked?
a. Every month, every 2 weeks when hot
b. Every 2 weeks, every week when hot
c. Every week, every 2 days when hot - CORRECT ANSWERS-b. Every 2 weeks, every
week when hot
When is it time to shock a public pool?
a. When combined chlorine > 0.2 ppm
b. When combined chlorine > 0.4 ppm
c. When combined chlorine > 0.6 ppm - CORRECT ANSWERS-a. When combined
chlorine > 0.2 ppm
How much chlorine is needed to shock?
a. Bring water to 2X value for CC
b. Bring water to 5 X value for CC
c. Bring water to 10 X value for CC
d. Bring water to 15 X value for CC - CORRECT ANSWERS-c. Bring water to 10X value
for CC
What kind of shock can be used when superchlorinating a brome pool?
a. Potassium monopersulfate
b. Potassium chloride
c. Potassium iodide - CORRECT ANSWERS-a. Potassium monopersulfate
Why would an operator use bromine sanitizer over chlorine sanitizer?
a. Cheaper
b. Easier to maintain pH
, c. Better residual
d. a and c - CORRECT ANSWERS-d. a and c
What is the ideal range of chlorine in swimming pools?
a. 1.0-4.0
b. 2.0-5.0
c. 3.0-6.0
d. 4.0-7.0 - CORRECT ANSWERS-a. 1.0-4.0
What is the ideal range of bromine in swimming pools?
a. 1.0-3.0
b. 3.0-5.0
c. 5.0-7.0 - CORRECT ANSWERS-b. 3.0-5.0
What is the allowed range of pH in pools?
a. 7.0-7.8
b. 7.0-8.0
c. 7.2-7.8
d. 7.2-8.0 - CORRECT ANSWERS-c. 7.2-7.8
What is the ideal range of alkalinity in pools?
a. 40-100 ppm
b. 60-120 ppm
c. 80-120 ppm
d. 80-140 ppm - CORRECT ANSWERS-c. 80-120 ppm
What is the ideal range of cyanuric acid in pools?
a. 10-100 ppm
b. 30-100 ppm
c. 50-100 ppm - CORRECT ANSWERS-b. 30-100 ppm
What kind of pools can bromine sanitizer NOT be used at?
a. Wading pools
b. Outdoor pools
c. Flume pools - CORRECT ANSWERS-b. Outdoor pools
Brome is easily destroyed by UV
What is the flow rate of DE filters?
a. 2.0 gpm/ft2
