CPI Water Balance & Chemical Testing 2

Question 1

What is the recommended pH range for pool water according to most health codes and APSP standards?

Accepted Answer

7.2–7.8

Answer

A pH of 7.2–7.8 is the standard recommended range, balancing sanitizer effectiveness and bather comfort.

Question 2

When testing total alkalinity, a result of 40 ppm would most likely cause which problem?

Accepted Answer

Rapid, uncontrolled pH fluctuations

Answer

Low alkalinity (below 80 ppm) removes pH buffering capacity, causing pH to swing dramatically with minor chemical additions.

Question 3

A DPD test kit measures which pool chemical parameter?

Accepted Answer

Free available chlorine

Answer

DPD (N,N-diethyl-p-phenylenediamine) reagent reacts with free available chlorine to produce a pink color for colorimetric testing.

Question 4

Which reagent is used in the FAS-DPD test method to determine the exact chlorine concentration by titration?

Accepted Answer

Ferrous ammonium sulfate

Answer

FAS (ferrous ammonium sulfate) is the titrant that decolorizes the DPD-chlorine complex, allowing precise chlorine measurement.

Question 5

A pool inspector observes milky white water in a freshly filled pool with a calcium hardness reading of 650 ppm. The MOST likely cause is:

Accepted Answer

Calcium carbonate precipitation

Answer

Extremely high calcium hardness combined with adequate alkalinity and pH can cause calcium carbonate to precipitate out of solution, creating cloudy water.

(CPI) Certified Pool & Spa Inspector Practice Test

(CPI) Certified Pool & Spa Inspector Practice Test

CPI Water Balance & Chemical Testing 2