NASCO Water Chemistry & Quality Control 4

Question 1

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

Accepted Answer

Every 8 hours

Answer

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

Question 2

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

Accepted Answer

Raise pH

Answer

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

Question 3

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

Accepted Answer

Cryptosporidium parvum

Answer

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

Question 4

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

Accepted Answer

It over-stabilizes chlorine, reducing its germicidal effectiveness

Answer

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

Question 5

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

Accepted Answer

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

Answer

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

(NASCO) National Aquatic Safety Company Aquatic Facility Operator Certification Practice Test

(NASCO) National Aquatic Safety Company Aquatic Facility Operator Certification Practice Test

NASCO Water Chemistry & Quality Control 4