Water Quality & Treatment Standards Flashcards
7 cards from real CPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Water Quality & Treatment Standards flashcards as text
An inspector tests a saltwater pool and finds the salt level at 2,000 ppm when the system calls for 3,200 ppm. What is the likely result?
Answer: The salt chlorine generator produces insufficient chlorine output
Salt chlorine generators require adequate salt concentration to function properly; low salt levels reduce chlorine production, potentially leaving the pool under-sanitized.
Which waterborne pathogen is most resistant to normal chlorine disinfection levels and requires special treatment protocols in pools?
Answer: Cryptosporidium parvum
Cryptosporidium oocysts are highly chlorine-tolerant, requiring UV or ozone treatment, or extremely high chlorine levels (hyperchlorination) for inactivation.
What is the correct action when a formed-stool fecal incident occurs in a public pool?
Answer: Close the pool, raise free chlorine to 2 ppm, maintain pH 7.5, and achieve a 25-minute CT value
CDC/MAHC guidelines for a formed-stool incident require closing the pool, achieving 2 ppm free chlorine at pH 7.5 for at least 25 minutes to inactivate E. coli.
What is the recommended maximum calcium hardness level for a plaster-finished pool to avoid scaling?
Answer: 400 ppm
Calcium hardness should generally be kept below 400 ppm in plaster pools to prevent scale deposits on surfaces and equipment.
A pool uses ozone (O3) as a supplemental sanitizer. What secondary disinfectant must still be maintained in the water?
Answer: A chlorine or bromine residual throughout the entire pool
Ozone is destroyed quickly and provides no residual protection; a chlorine or bromine residual must still be maintained throughout the pool for ongoing sanitation.
Which test method provides the most accurate measurement of free chlorine in a pool with high cyanuric acid levels?
Answer: FAS-DPD (ferrous ammonium sulfate) titration
FAS-DPD titration is more accurate than colorimetric DPD in stabilized pools because cyanuric acid can bleach DPD color rapidly, causing underreading.
An inspector observes green staining on the pool walls and floor with a measured copper level of 0.8 ppm. What is the most likely cause?
Answer: Copper from ionizer, algaecide, or corroded copper pipes oxidizing and depositing on surfaces
Elevated copper (from ionizers, copper-based algaecides, or corroded copper plumbing) oxidizes and deposits as green staining on pool surfaces.