CPO Pool Calculations and Formulas Questions and Answers 2

Question 1

A rectangular pool is 75 feet long, 42 feet wide, and has an average depth of 5.5 feet. What is the pool volume in gallons?

Accepted Answer

130,178 gallons

Answer

Volume equals length times width times depth times 7.48 gallons per cubic foot: 75 times 42 times 5.5 times 7.48 equals approximately 130,178 gallons.

Question 2

How many pounds of calcium hypochlorite (65 percent available chlorine) are needed to raise the free chlorine by 2.0 ppm in a 50,000-gallon pool?

Accepted Answer

1.28 pounds

Answer

Using standard dosing references, approximately 1.28 pounds of 65 percent cal-hypo is needed for this adjustment.

Question 3

A circular spa has a diameter of 8 feet and a uniform depth of 3.5 feet. What is its volume in gallons?

Accepted Answer

1,316 gallons

Answer

Circular volume equals pi times radius squared times depth times 7.48: 3.14 times 16 times 3.5 times 7.48 equals approximately 1,316 gallons.

Question 4

What flow rate in GPM is required for a 120,000-gallon pool to achieve a 6-hour turnover?

Accepted Answer

333 GPM

Answer

Flow rate equals pool volume divided by turnover time in minutes: 120,000 divided by 360 equals 333 GPM.

Question 5

The Langelier Saturation Index of a pool reads negative 0.5. What does this indicate?

Accepted Answer

The water is corrosive

Answer

A negative LSI value indicates corrosive water that will dissolve calcium from plaster, grout, and metal surfaces. The ideal LSI range is negative 0.3 to positive 0.3.

CPO (Certified Pool Operator Exam) Practice Test

CPO (Certified Pool Operator Exam) Practice Test

CPO Pool Calculations and Formulas Questions and Answers 2