CPI Water Quality & Treatment Standards 2

Question 1

What is the recommended cyanuric acid (stabilizer) concentration range for outdoor residential pools?

Accepted Answer

30–50 ppm

Answer

Cyanuric acid should be kept between 30–50 ppm to effectively stabilize chlorine without over-inhibiting its sanitizing ability.

Question 2

A pool inspector notices the water is cloudy but the chlorine reading is within range. Which parameter should be checked next?

Accepted Answer

Filtration turnover rate and filter condition

Answer

Cloudy water with adequate chlorine typically indicates inadequate filtration, a dirty filter, or insufficient turnover rate.

Question 3

Which condition describes 'combined chlorine' (chloramines) in pool water?

Accepted Answer

Chlorine bound to ammonia or nitrogen compounds

Answer

Combined chlorine forms when free chlorine reacts with ammonia or nitrogenous waste, producing chloramines that cause odor and eye irritation.

Question 4

What is the minimum free chlorine level recommended by the Model Aquatic Health Code (MAHC) for a public pool?

Accepted Answer

1.0 ppm

Answer

The MAHC recommends a minimum free chlorine level of 1.0 ppm for public pools to ensure adequate disinfection.

Question 5

An inspector finds a pool's total alkalinity at 220 ppm. What is the primary concern?

Accepted Answer

pH will resist adjustment and scale formation is likely

Answer

High total alkalinity (above 180 ppm) causes pH to resist change ('pH lock') and promotes calcium carbonate scale formation.

(CPI) Certified Pool & Spa Inspector Practice Test