Pool Calculations and Formulas Flashcards

A rectangular pool is 75 feet long, 30 feet wide, and has an average depth of 6 feet. Using 7.5 gallons per cubic foot, what is the pool volume in gallons?

Answer: 101,250 gallons

Volume = length × width × average depth × 7.5 = 75 × 30 × 6 × 7.5 = 101,250 gallons.

A circular pool has a radius of 15 feet and an average depth of 5 feet. Using π ≈ 3.14, what is the volume in gallons?

Answer: 26,494 gallons

Volume = π × r² × depth × 7.5 = 3.14 × 225 × 5 × 7.5 ≈ 26,494 gallons.

A pool contains 120,000 gallons and state code requires the water to turn over every 6 hours. What minimum pump flow rate in GPM is required?

Answer: 333 GPM

Divide pool volume by turnover time in minutes: 120,000 ÷ (6 × 60) = 120,000 ÷ 360 = 333 GPM.

Which constant is used when calculating the volume of an oval (elliptical) pool?

Answer: 5.9

Oval pool volume = length × width × average depth × 5.9, where 5.9 accounts for the elliptical shape (≈ π/4 × 7.5).

A pool pump operates at 250 GPM. How many gallons does it circulate in 8 hours of continuous operation?

Answer: 120,000 gallons

250 GPM × 60 min/hr × 8 hr = 120,000 gallons circulated in 8 hours.

A pool with an irregular shape has a measured surface area of 800 square feet and an average depth of 4 feet. What is the pool volume in gallons?

Answer: 24,000 gallons

Volume = surface area × average depth × 7.5 = 800 × 4 × 7.5 = 24,000 gallons.

A small spa holds 600 gallons and local code requires it to turn over every 30 minutes. What minimum flow rate in GPM is required?

Answer: 20 GPM

GPM = pool volume ÷ turnover time in minutes = 600 ÷ 30 = 20 GPM.