Water Testing and Analysis 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 Water Testing and Analysis flashcards as text
The Langelier Saturation Index (LSI) is primarily used by pool operators to determine:
Answer: Whether pool water is corrosive or scale-forming
The LSI calculates the tendency of water to dissolve calcium carbonate (corrosive) or deposit it as scale, based on pH, temperature, calcium hardness, alkalinity, and TDS.
A Langelier Saturation Index (LSI) value of +0.5 indicates that the pool water is:
Answer: Tending toward scale formation on surfaces and equipment
An LSI above 0 indicates scale-forming water; a value of +0.5 is moderately scale-forming and may deposit calcium carbonate on pool surfaces and equipment.
When pool water total dissolved solids (TDS) reach levels that impair water quality and chemical efficiency, the primary corrective action is to:
Answer: Partially drain and refill with fresh source water
Dilution through partial drain-and-refill is the only effective method to lower TDS, as filtration cannot remove dissolved ionic compounds.
The five factors used to calculate the Langelier Saturation Index (LSI) are pH, temperature, calcium hardness, total alkalinity, and:
Answer: Total dissolved solids (TDS)
TDS is the fifth LSI factor, represented by a correction value that adjusts the saturation index for dissolved mineral content in the water.
Under normal operating conditions, how frequently should chemical testing be performed at an open public swimming pool?
Answer: At least every two hours during hours of operation
Most state health codes require public pool operators to test and log chlorine and pH levels at least every two hours during operation to ensure continuous bather safety.
When performing a drop-count total alkalinity titration test, the test result in ppm is calculated by:
Answer: Multiplying the total number of drops used by the kit's dilution factor
In drop-count titration, each drop represents a fixed increment of alkalinity; the total drops multiplied by the kit's factor (commonly 10) gives the alkalinity in ppm.
How does cold water temperature (below 60°F) affect colorimetric pool water test results?
Answer: Cold water slows reagent reactions and can impair accurate color development
Most chemical test reagents are calibrated for near-room-temperature water; very cold water slows reaction kinetics and may yield pale or incomplete color development.