Disinfection Systems & Sanitization Methods Flashcards

What is the primary purpose of adding chlorine to pool and spa water?

Answer: To kill or inactivate harmful microorganisms and pathogens

Chlorine acts as the primary disinfectant in pool and spa water, killing bacteria, viruses, and other pathogens to protect bather health.

Which form of chlorine is most commonly used in residential and small commercial pools due to its convenience as a slow-dissolving tablet?

Answer: Trichloroisocyanuric acid (trichlor)

Trichlor tablets dissolve slowly in feeders or floaters, providing a convenient and consistent chlorine source, and they contain cyanuric acid as a built-in stabilizer.

According to standard pool health codes, what is the generally accepted minimum free chlorine level for a public swimming pool?

Answer: 1.0 ppm

Most health departments require a minimum of 1.0 ppm free chlorine in public pools to ensure adequate disinfection and bather safety.

What do chloramines (combined chlorine) in pool water indicate?

Answer: Chlorine that has combined with nitrogen-containing compounds from bathers

Chloramines form when free chlorine reacts with ammonia and other nitrogen compounds introduced by bathers (sweat, urine, body oils), and they are poor disinfectants that cause eye irritation and the 'chlorine smell.'

What is breakpoint chlorination, and why is it performed?

Answer: Adding enough chlorine (typically 10× the combined chlorine level) to oxidize and destroy chloramines

Breakpoint chlorination requires adding chlorine at approximately 10 times the combined chlorine level to chemically destroy chloramines and restore the pool's disinfection effectiveness.

What is the ideal pH range for maximizing chlorine's disinfection effectiveness in a pool?

Answer: 7.2 – 7.8

At a pH of 7.2–7.8, a sufficient proportion of chlorine exists as hypochlorous acid (HOCl), the active disinfecting form, balancing effectiveness with bather comfort.

Calcium hypochlorite (Cal-hypo) has approximately what available chlorine content by weight?

Answer: 65–70%

Calcium hypochlorite granules typically contain 65–70% available chlorine, making them a highly concentrated and effective shock treatment product.