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Pool Gallons - CPO® Math Tutorial

Knowing how to calculate volume in gallons is important for determining chemical changes, flow rates, and in some states, bather loads in pools.

Things to know about Gallons

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The pool volume as expressed in gallons:

  • Cubic feet or cubic meters are not useful in everyday discussions. So we take it
    one step further and convert to gallons or liters, things we know.
  • Volume (V)gallons = Volume (V)cubic feet x 7.5

    The actual number of gallons in a cubic foot is 7.48. The number 7.5 is used
    to make calculations easier. The amount of error in a 60,000 gallon pool would
    be only 160.5 gallons.
Examples:

  • Using the same pool from the previous section:Gallons

    The formula is V = A times AD
    A = L x W
    AD = (D1 + D2) divided by 2
    A = 40 ft x 20 ft = 800 sq.ft.
    AD = (3 feet+ 7 feet) divided by 2 = 5 feet
    V = A times AD
    V = 800 sq.ft. times 5 feet
    V = 4,000 cubic feet (cu.ft.)
  • Volume (V)gallons = Volume (V)cubic feet x 7.5

    (V)gallons = 4,000 cubic feet x 7.5
    (V)gallons = 30,000 gallons
What is the volume in gallons of a rectangular pool with a length of 60 feet and a
width of 30 feet, having a shallow-end depth of 3 feet and a deep-end depth of 7 feet?
We will continue to use a series of 'plug-and play' boxes as they are applied in the
CPO® class. Just plug the correct number as given by the problem a
perform the math (play) as indicated.
The formula for a pool volume in gallons is: V = A times AD times 7.5
You may wish to look back on the Main Page. Under things to know
it gave you - One cubic foot of water contains 7.5 gallons.
V = x x 7.5
A = L x W
Length = 60 feet; W = 30 feet
Pool Volume

Area = 60 ft x 30 feet = 1800 sq.ft.
AD = (D1 + D2) divided by 2
D1 = 3 feet; D2 = 7 feet

AD = (3 feet + 7 feet) divided by 2
AD = 10 feet divided by 2 = 5 feet
V = x x 7.5 =

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