itten wrote:
This is the text of the formula I copied


CALCULATING YOUR POND'S WATER VOLUME

It is extremely important to know the approximate water volume of
your pond before administering any water conditioner, algacide or
medication. Underdosing will usually not be effective and overdosing
the water can cause problems for your fish. For some, these
calculations will not be difficult; however, some of the winding,
curving waterfalls or free form fountains may make finding the water
volume of your pond a mind bending experience.

SHAPE OF POND CALCULATION OF WATER VOLUME (IN FEET)

Rectanguar or Square Length X Width X 7.5 gallons

Circular Diameter X Diameter X Depth X 5.9 gallons

Oval with straight sides Length X Width X Depth X 6.7 gallons


Someone just missed out the word X Depth in the rectangular formula. The
other two have it.

Thanks, very useful.
--
Quilljar

Flight by machines heavier than air is unpractical and insignificant,
if not utterly impossible Simon Newcomb US Astronomer 1902