Pool Maintenance and Troubleshooting Flashcards
7 cards from real CPO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pool Maintenance and Troubleshooting flashcards as text
A commercial pool holds 120,000 gallons and must achieve a maximum 6-hour turnover rate. What is the minimum required flow rate?
Answer: 333 GPM
Flow rate = volume ÷ turnover time in minutes = 120,000 ÷ (6 × 60) = 120,000 ÷ 360 = 333 GPM.
When cyanuric acid (CYA) in a pool exceeds 100 ppm, the primary concern is:
Answer: Significant reduction in chlorine effectiveness, requiring dangerously high chlorine concentrations to compensate
High CYA creates 'chlorine lock' — the stabilizer binds free chlorine so tightly that effective disinfection becomes difficult even at elevated chlorine readings.
Calcium hardness below 150 ppm primarily causes which type of damage?
Answer: Aggressive, corrosive water that etches plaster and corrodes metal fittings and equipment
Water deficient in calcium becomes aggressive and seeks calcium by dissolving it from plaster, grout, and metal fittings, causing etching and corrosion damage.
A Langelier Saturation Index (LSI) value of 0.0 indicates the pool water is:
Answer: Perfectly balanced — neither scale-forming nor corrosive
An LSI of 0.0 represents ideal water balance; positive values indicate scale-forming tendency while negative values indicate a corrosive tendency.
When total dissolved solids (TDS) exceed recommended levels (typically 1,500 ppm above source water), the corrective action is:
Answer: Partially drain the pool and refill with fresh water to dilute the TDS
TDS can only be reduced by dilution — draining a portion of the pool and replacing it with fresh water is the only effective corrective measure.
When closing a pool for winter in a freezing climate, the water level should be:
Answer: Lowered below the skimmer inlets and return fittings to prevent freeze cracking of those components
Lowering water below the skimmer and return lines removes standing water from the fittings most vulnerable to freeze damage, preventing cracks from ice expansion.
What is the correct order for adjusting pool water chemistry when balancing a pool?
Answer: Total alkalinity → pH → calcium hardness → sanitizer
Total alkalinity is adjusted first because it buffers and stabilizes pH; once alkalinity is correct, pH is adjusted, then calcium hardness, with sanitizer added last to avoid chemical interference.