Pool Operator Midterm Exam 2025

whole range chlorine in a pool: ____ to _____ - Correct Ans-1, 5 ideal range chlorine in a pool: ____ to _____ - Correct Ans-2, 4 whole range chlorine in a spa: ____ to _____ - Correct Ans-2, 10 ideal range chlorine in a spa: ____ to _____ - Correct Ans-3, 5 4 types of solid chlorine - Correct Ans-calcium hypochlorite, lithium hypochlorite, trichlor, dichlor liquid chlorine - Correct Ans-sodium hypochlorite (NaOCl) how active is gas chlorine - Correct Ans-100% the active killing form of chlorine in water - Correct Ans-hypochlorous acid (HOCl) HOCl = ______ - Correct Ans-H+ (hydrogen ion) + OCl- (hypochlorite ion) most common granular chlorine (pH range) - Correct Ans-calcium hypochlorite (8.5 - 11, used to super chlorinate water) not common form of chlorine due to low active strength (pH) - Correct Ans-lithium hypochlorite (10.8) tablet/stick chlorine usually used in erosion feeder (pH - what will it do?) - Correct Ans-trichlor (2.8 - 3.5, lower alkalinity and pH over time) salt used as a disinfectant (pH) - Correct Ans-dichlor (6.7 - common in vinyl lined pools) most common type of chlorine used (pH) - Correct Ans-sodium hypochlorite (NaOCl - 13) ______ needs special training to use and has a pH of ____ and will _____ when added to water - Correct Ans-gas chlorine, 0, lower pH chlorine is most effective as a pH of _____ - Correct Ans-7.5 active disinfectant in the water - Correct Ans-free chlorine (FC) FC is determined by the ______ test and is maintained between ____ and ____ ppm - Correct Ans-DPD, 2, 4 equal to the amount of hypochlorous acid (HOCl) and the amt of hypochlorite ions (OCl-) - Correct Ans-free chlorine (fc) the result of free chlorine reacting with organic compounds - Correct Ans-combine chlorine (CC) common name and max for pools and spas for combine chlorine - Correct Ans-chloramines, 0.2, 0.5 CC = - Correct Ans-TC - FC what will a DPD measure - Correct Ans-TC, FC how much CC should a pool have ideally - Correct Ans-zero shocking the pool is also called - Correct Ans-breakpoint chlorination breakpoint chlorination is the conversion of ________ into ______ - Correct Ans-combine chlorine, nitrogen gas breakpoint chlorination equation - Correct Ans-BPC = 10 x CC [BPC = 10 x (TC - FC)] whole cyanuric acid range: _____ to ______ppm - Correct Ans-0, 100 ideal cyanuric acid range: _____ to ______ ppm - Correct Ans-30, 50 acts as a protection for chlorine compounds from UV light - Correct Ans-cyanuric acid CyA will act as a stabilizer for _______ but does not stabilize ________ - Correct Ans-free chlorine, bromine The only way to reduce CyA concentration is to _______ - Correct Ans-dilute the water and replace it whole range of bromine: ____ to _____ - Correct Ans-2, 10 ideal range of bromine: _____ to ______ - Correct Ans-4, 6 second most common disinfectant in the pool - Correct Ans-bromine two types of bromine used - Correct Ans-sodium bromide, solid bromide Bromine in natural form is a ______ but is in _____ form when added to pools - Correct Ans-reddish brown liquid, solid __________ is similar to hypochlorous acid - Correct Ans-hypobromous acid bromine releases _____ and _____ when added to water - Correct Ans-hypobromite ion, hydrogen ion bromine will ______ pH when added to water - Correct Ans-lower whole range of pH: ____to_____ - Correct Ans-7.2, 7.8 ideal range of pH: ____ to ____ - Correct Ans-7.4, 7.6 things that influence pH (6) - Correct Ans-swimmer waste, disinfectants, water source, air borne debris, chemical balance, evaporation low pH leads to (3) - Correct Ans-corrosive water, surface staining, surface etching if you have low pH, you must add - Correct Ans-soda ash (caustic soda - sodium carbonate) high pH leads to (5) - Correct Ans-scaling water, cloudy water, clogged filters, reduced circulation, eye/skin irritation if you have high pH, you must add ____ or _____ - Correct Ans-muriatic acid, sodium bisulfate whole range of total alkalinity: ____ to _____ - Correct Ans-60, 180 ideal range(s) of total alkalinity: ____ to _____ - Correct Ans-80, 120 the measure of the ability of the water to resist change in pH - Correct Ans-total alkalinity acts as a pH buffer - Correct Ans-total alkalinity _____ will affect total alkalinity - Correct Ans-cyanuric acid if your pH is high, you will require a ______ total alkalinity - Correct Ans-lower if your pH is low, it is acceptable to have a ______ total alkalinity - Correct Ans-higher low total alkalinity leads to (4) - Correct Ans-pH bounce, heater failure, surface etching, green water if you have low total alkalinity, add ___