Advanced Professional Practice Flashcards

A pool operator wants to calculate the Langelier Saturation Index (LSI). Which set of factors is required?

Answer: pH, temperature, calcium hardness, total alkalinity, TDS

The LSI is calculated using pH, water temperature, calcium hardness, total alkalinity, and TDS to assess water balance and corrosion/scale potential.

A pool using a saltwater chlorine generator (SWG) shows consistently low free chlorine despite the generator running at 100%. The MOST likely cause is:

Answer: Low salt concentration in the water

If CYA is very high, chlorine activity is suppressed, but low salt concentration directly reduces the amount of chlorine the electrolytic cell can generate.

Under OSHA standards, which personal protective equipment (PPE) is required when handling concentrated (35%) sodium hypochlorite?

Answer: Chemical-resistant gloves, goggles, and apron

Concentrated hypochlorite is a strong oxidizer and corrosive; OSHA requires chemical-resistant gloves, splash goggles, and a protective apron to prevent skin and eye injury.

A public pool must post maximum bather load (MBL) calculations. Using the standing room formula, a pool with 1,200 sq ft of surface area yields an MBL of:

Answer: 200 bathers

The standing room formula uses 6 sq ft per bather: 1,200 ÷ 6 = 200 bathers maximum.

A pool operator discovers that the ORP (oxidation-reduction potential) reading is 650 mV but free chlorine measures 1.5 ppm. The BEST explanation is:

Answer: High CYA is reducing chlorine's oxidizing power despite adequate free chlorine

CYA binds free chlorine and lowers ORP; even with measurable free chlorine, high CYA reduces the electrochemical activity that ORP sensors detect.

Which disinfection byproduct (DBP) is associated with the reaction of chlorine with nitrogen-containing compounds from bathers?

Answer: Chloramines (combined chlorine)

Chloramines form when free chlorine reacts with nitrogen compounds (urea, sweat, urine) introduced by bathers, producing eye irritation and the characteristic pool odor.

A pool operator is responding to a fecal incident involving formed stool. According to CDC Healthy Swimming guidelines, the pool should be:

Answer: Closed and shock-treated to 2 ppm free chlorine at pH 7.5 for 25 minutes

For formed-stool fecal incidents (non-diarrheal), CDC recommends raising free chlorine to 2 ppm at pH 7.5 for a 25-minute contact time before reopening.