Pool Water Chemistry 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 Water Chemistry flashcards as text
What is the recommended pH range for swimming pool water according to CPO standards?
Answer: 7.2–7.8
The CPO-recommended pH range is 7.2–7.8, with 7.4–7.6 considered optimal for bather comfort and chlorine effectiveness.
Which chemical is commonly used to LOWER pH in pool water?
Answer: Muriatic acid (hydrochloric acid)
Muriatic acid (hydrochloric acid) or sodium bisulfate are the standard chemicals used to decrease pool pH.
Total alkalinity in pool water primarily serves as a buffer against changes in:
Answer: pH
Total alkalinity resists rapid pH swings by neutralizing acids and bases, keeping pH stable.
What is the ideal total alkalinity range for swimming pools?
Answer: 80–120 ppm
The CPO-recommended total alkalinity range is 80–120 ppm to maintain adequate pH buffering.
When pool pH rises above 7.8, what happens to free chlorine effectiveness?
Answer: It decreases significantly
At pH above 7.8, hypochlorous acid (the active disinfectant) converts to the less effective hypochlorite ion, reducing sanitizing power.
The Langelier Saturation Index (LSI) is used to determine:
Answer: Whether water is corrosive or scale-forming
The LSI calculates water balance by combining pH, temperature, alkalinity, calcium hardness, and TDS to predict corrosion or scale tendency.
Which chemical is used to raise total alkalinity without significantly raising pH?
Answer: Sodium bicarbonate
Sodium bicarbonate (baking soda) effectively raises total alkalinity with a minimal effect on pH compared to soda ash.