Water Chemistry & Quality Control Flashcards

What is the typical recommended turnover rate for a competition pool?

Answer: Every 8 hours

A standard competition or general lap pool typically requires a complete water turnover every 8 hours (or 3 turnovers per day).

Sodium carbonate (soda ash) is added to pool water primarily to:

Answer: Raise pH

Soda ash (sodium carbonate) is a strong base used to raise pH when it falls below the acceptable range of 7.2–7.8.

Which pathogen is MOST resistant to normal chlorine levels and requires significantly higher contact time or UV/ozone treatment?

Answer: Cryptosporidium parvum

Cryptosporidium oocysts are extremely resistant to chlorine and typically require UV light or ozone for effective inactivation.

What effect does high cyanuric acid (above 100 ppm) have on pool sanitation?

Answer: It over-stabilizes chlorine, reducing its germicidal effectiveness

Excessive cyanuric acid binds chlorine so tightly that the chlorine becomes much less effective at killing pathogens — a condition called 'chlorine lock'.

When testing pool water, samples should be collected from where?

Answer: At least 12–18 inches below the surface away from inlets

Water samples should be taken at elbow depth (12–18 inches below surface) away from inlets to get a representative reading of pool conditions.

What is the function of a pool's recirculation system in relation to water chemistry?

Answer: It distributes chemicals evenly and removes debris through filtration

The recirculation system circulates water through the filter, ensuring even chemical distribution and removal of suspended particles and contaminants.

Which chemical combination is DANGEROUS and must never be mixed together?

Answer: Calcium hypochlorite and trichlor (trichloroisocyanuric acid)

Mixing calcium hypochlorite with trichlor can cause violent chemical reactions, fires, or explosions due to their incompatible chemistry.