Pool & Spa Maintenance & Operations Flashcards

Which algae type is the most difficult to eliminate from a pool and typically requires brushing and a specialized algaecide?

Answer: Black algae

Black algae has a protective outer layer and root-like structures called holdfasts that penetrate porous surfaces, making it the most resistant to treatment.

What is the recommended free chlorine residual range for a stabilized outdoor pool using cyanuric acid?

Answer: 1–3 ppm

The standard free chlorine range for pools with cyanuric acid (stabilized) is 1–3 ppm to maintain effective sanitation.

A pool's total dissolved solids (TDS) level is very high. What is the most effective corrective action?

Answer: Partially drain and refill with fresh water

High TDS can only be reduced by replacing pool water, as dissolved solids accumulate over time and cannot be removed by chemical treatment or filtration alone.

What is the minimum depth of water required for a diving board with a 1-meter height above water in a commercial pool?

Answer: 9 feet (2.7 m)

A 1-meter diving board requires a minimum water depth of approximately 9 feet (2.7 m) at the plunge point per most health codes and ANSI/NSPI standards.

What is 'breakpoint chlorination'?

Answer: Adding enough chlorine to oxidize all combined chlorine and organic matter, leaving only free chlorine

Breakpoint chlorination is reached when enough chlorine is added (typically 10:1 ratio to combined chlorine) to destroy all chloramines and leave only free available chlorine.

A pool operator notices white, chalky deposits forming on the tile at the waterline. What is the most likely cause?

Answer: High calcium hardness and high pH causing calcium carbonate to scale out

Calcium carbonate scale deposits form when calcium hardness is high and pH is elevated, causing calcium to precipitate out of solution onto pool surfaces.

Which federal law mandates anti-entrapment drain covers in public pools and spas?

Answer: Virginia Graeme Baker Pool and Spa Safety Act (VGB Act)

The Virginia Graeme Baker Pool and Spa Safety Act (enacted 2007) requires anti-entrapment drain covers and safety systems in public pools and spas to prevent suction entrapment.