CAT Aquatic Technicians Skills and Knowledge Areas 4

Question 1

When a variable-speed pump (VSP) is programmed for low-speed operation at night, what is the primary benefit over a single-speed pump?

Accepted Answer

Significantly reduced energy consumption while still maintaining circulation

Answer

Variable-speed pumps can reduce speed and consume up to 90% less energy at low speeds because power consumption is proportional to the cube of the speed.

Question 2

A pool with a volume of 20,000 gallons uses a pump with a flow rate of 40 GPM. What is the turnover time?

Accepted Answer

8.3 hours

Answer

Turnover time = pool volume ÷ flow rate = 20,000 ÷ 40 GPM = 500 minutes = approximately 8.3 hours.

Question 3

Black algae in a pool is particularly difficult to eradicate because:

Accepted Answer

It forms a protective outer layer and roots into porous surfaces like plaster

Answer

Black algae has a protective outer coating and roots deeply into porous surfaces, requiring aggressive brushing and high chlorine treatment to eliminate.

Question 4

What is the maximum recommended cyanuric acid (CYA) level for a residential outdoor pool to maintain chlorine effectiveness?

Accepted Answer

100 ppm

Answer

The recommended maximum CYA for residential pools is 100 ppm, as higher levels significantly reduce chlorine's ability to kill pathogens (chlorine lock).

Question 5

A pool customer complains of green water despite adequate chlorine readings. After checking, the technician finds no algae. What is the most likely explanation?

Accepted Answer

Dissolved metals (typically copper or iron) in the water

Answer

Dissolved copper or iron in pool water can turn water green or brown, especially after shocking, even without algae present.

(CAT) Certified Aquatic Technicians Practice Test

(CAT) Certified Aquatic Technicians Practice Test

CAT Aquatic Technicians Skills and Knowledge Areas 4