CPO Disinfection Systems & Sanitization Methods 3

Question 1

When chlorine reacts with ammonia in pool water (from bather waste), which harmful byproduct is primarily formed?

Accepted Answer

Chloramines (combined chlorine)

Answer

When free chlorine reacts with ammonia and organic nitrogen compounds, it forms chloramines (combined chlorine), which are poor disinfectants, cause eye and skin irritation, and produce the characteristic 'pool smell.'

Question 2

How frequently must a CPO or pool operator test and record free chlorine and pH levels in a public pool according to typical health department requirements?

Accepted Answer

At least every 2 hours during operating hours

Answer

Most public pool health codes require operators to test and record free chlorine and pH levels at least every two hours during operation to ensure continuous safe sanitation.

Question 3

What is the recommended relationship between free chlorine (FC) and cyanuric acid (CYA) levels to maintain effective sanitation in a stabilized pool?

Accepted Answer

FC should be at least 7.5% of the CYA level

Answer

The minimum free chlorine level should be at least 7.5% of the cyanuric acid level (e.g., CYA of 40 ppm requires minimum FC of 3 ppm) to ensure adequate active disinfection despite CYA binding.

Question 4

Bromine is often preferred over chlorine as a sanitizer for spas and hot tubs because:

Accepted Answer

Bromine remains effective at higher temperatures and higher pH levels common in spas

Answer

Bromine maintains its disinfection effectiveness at the elevated temperatures (98–104°F) and higher pH levels typical of spas, whereas chlorine degrades rapidly under these conditions.

Question 5

What is the purpose of a 'dichlor' (sodium dichloro-s-triazinetriene) shock treatment compared to a 'non-chlorine shock' (potassium monopersulfate)?

Accepted Answer

Dichlor adds chlorine and stabilizer; non-chlorine shock only oxidizes without adding chlorine or CYA

Answer

Dichlor shock adds both available chlorine and cyanuric acid stabilizer, while potassium monopersulfate (non-chlorine shock) is a pure oxidizer that destroys organic waste without contributing chlorine or CYA.

(CPO) Certified Pool and Spa Operator Practice Test

(CPO) Certified Pool and Spa Operator Practice Test

CPO Disinfection Systems & Sanitization Methods 3