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Copyright © 2020. All rights reserved • 95 North Oak Street • Kendallville, IN 46755
PERFORMANCE
1. Find Your Pool Size
Use the formulas below to find the capacity of your pool.
• Rectangular Pools: Length (ft.) x Width (ft.) x Average Depth (ft.) x 7.5 = Total pool capacity in gallons
• Circular Pools: Diameter (ft.) x Diameter (ft.) x Average Depth (ft.) x 5.9 = Total pool capacity in gallons
• Oval Pools: Length (ft.) x Width (ft.) x Average Depth (ft.) x 6.7 = Total pool capacity in gallons
Example for Rectangular Pool:
40 ft. L x 20 ft. W x 6 ft. average depth x 7.5 = 36,000 gallon capacity pool
2. Calculate Flow Rate, Gallons Per Minute (GPM) and Turnover
Pools should typically turn water over once every 8 hours. Use this flow rate formula along with your pool
capacity from step 1 to find the Gallons Per Minute (GPM) you need for your system:
Pool Volume in Gallons ÷ Turnover Rate in Minutes = Flow Rate
Example:
If you have a 30,000-gallon pool and you want the water to turn over once every eight hours:
30,000 ÷ 480 (60 minutes x 8 hours) = 62.5 GPM
Your 30,000-gallon pool needs 62.5 gallons per minute to circulate the water once every eight hours.
3. Calculate Maximum Flow Rate
This number helps you match the pump with your pool filter. Your pool filter has a maximum flow rate, which
is measured in GPM. The GPM rating of the pump should be less than the GPM rating of the pool filter. If the
pump is rated higher than the filter, the filter is undersized and will not work properly.
The size of your pool pipes determines the maximum flow rate for your system.
Count the number of intake lines for your pool and reference the pipe sizes below:
• For each 1.5-inch intake line, the maximum flow rate is 42 GPM.
• For each 2-inch intake line, the maximum flow rate is 73 GPM.
Example:
Two 1.5-inch intake lines = 84. The maximum flow rate is 84 GPM.
4. Calculate Resistance
Every piece of equipment in the pump system creates resistance to water flow. Pipe length and size, type of
filter, heaters and pool cleaners all add to this resistance.
The easiest way to find resistance is to use a pressure meter and these formulas:
• Check the pressure of water flowing into the filter tank and multiply that number by 2.31.
• Check the vacuum reading on the pump suction line and multiply that by 1.13.
• Add the two numbers together to find is the resistance, or total dynamic head.
Example:
If the water flowing into the filter tank is 15 PSI, and the vacuum reading on the pump suction line
is 6 PSI:
Water flow into filter tank: 15 PSI x 2.31 = 34.65
Vacuum reading on pump suction line: 6 PSI x 1.13 = 6.78
Total = 41.43 ft. of resistance or TDH
Use the chart below to determine expected gallons per minute for your installation.
SPECIFICATIONS
MODEL
HP
PERFORMANCE IN GALLONS PER MINUTE
20’ TDH
30’ TDH
40’ TDH
50’ TDH
60’ TDH
70’ TDH
148014
1
90
80
64
43
16
-
025191
1.65
110
100
90
79
62
47
