CAT Aquatic Technicians Skills and Knowledge Areas 2

Question 1

A pool's total alkalinity reads 60 ppm. What is the most likely consequence if left uncorrected?

Accepted Answer

pH will fluctuate widely and be difficult to control

Answer

Low total alkalinity (below 80 ppm) causes pH to bounce dramatically, making water chemistry difficult to manage.

Question 2

Which type of filter media requires backwashing to clean and uses the finest filtration of the three common types?

Accepted Answer

Diatomaceous Earth (DE)

Answer

DE filters provide the finest filtration (3–5 microns) and are cleaned by backwashing, after which fresh DE must be added.

Question 3

When shocking a pool with calcium hypochlorite, a technician should always:

Accepted Answer

Pre-dissolve the shock in a bucket of pool water before adding

Answer

Pre-dissolving calcium hypochlorite prevents bleaching of the pool surface and ensures even distribution.

Question 4

A residential pool pump is running but flow rate has dropped significantly. The filter pressure gauge reads normal. What is the most likely cause?

Accepted Answer

Worn pump impeller or clogged pump strainer basket

Answer

A clogged pump strainer basket or worn impeller restricts water intake, reducing flow rate while filter pressure may appear unaffected.

Question 5

What is the recommended free chlorine level (in ppm) for a residential swimming pool according to standard industry guidelines?

Accepted Answer

1.0–3.0 ppm

Answer

The standard recommended free chlorine range for residential pools is 1.0–3.0 ppm to ensure effective sanitation without irritation.

(CAT) Certified Aquatic Technicians Practice Test