Dallas - Ft. Worth Area Monthly Weather Averages
Calculating Pond Volume
It is vital to know the volume of your pond in gallons in order to properly size pumps, filters and dispense pond chemicals. Pond volume in gallons can be initially calculated from the following: pond length (in feet) times the pond width (in feet) times the pond depth (in feet) times 7.48 (gallons in a cubic foot).
Geometric shapes are simple to calculate, i.e., squares and rectangles. The gallons of a round pond can be obtained from: pond radius (in feet) times the pond radius (in feet) times Pi (3.1415) times the pond depth (in feet) times 7.48 (gallons per cubic foot) .
Many garden ponds are free form in shape. The gallons of these ponds can be estimated by dividing the pond surface into several more familiar geometric shapes, i.e., squares and circles, calculating the gallons of each section and then summing the gallons of all sections.
Example: Our pond is 16 X 8 X 4.5 deep. So the surface area is 16 X 8 = 128 square feet. 128 square feet X 4.5 of depth = 576 cubic feet. 576 cubic feet X 7.48 = 4,308.48 gallons of capacity in the pond.
Remember that the approach will give you an estimate of the pond volume. It will not include the water in your filters, plumbing lines, waterfalls, other other areas. To accurately determine the total system volume, fill the pond using a water meter. You can use the water meter on your house to do this. Note the meter reading before starting and when the pond system is full. Please do not operate clothes washing machines, dish washers, and other devices that use a significant amount of water while the pond is being filled.
Calculating Pond Heater Size in BTU/hr:
Option A for Heat loss calculation for uncovered pond:
Heat loss (Btu/hr) = 12 X pond surface area X desired pond temperature - coldest ambient temp.
Example: Pond is 9 feet wide and fifteen feet long, uncovered surface. I want the pond around 70F and it gets down to 28F at night. Sometimes colder, sometimes warmer. Here's the math: 12 X (9ft x 15ft) X [70F minus 28F at night]. Works out to: 12 X 135 sq. ft. X 42F margins. = 68,040 BTU/hr.
Option B for Heat loss calculation for almost completely covered pond:
Heat loss (Btu/hr) = pond surface area X desired pond temp. - coldest ambient temp. Make sure an airspace is maintained between the surface of the pond and the cover. Do not float the cover directly on the pond.
Example: Pond is 9 feet wide and fifteen feet long, with a covered surface. I want the pond around 70F and it gets down to 28F at night. Sometimes colder, sometimes warmer. Here's the math: (9ft X 15ft) X [70F minus 28F at night]. Works out to: 135 sq. ft. X 42F margins. = 5,670 BTU/hr.