Freshwater

find the following simple tables quite helpful. (Saves on calculator
batteries, too.)
Many tropical fish magazines and books use different types of systems to get
their mathematical points across. One publication may choose to use the
metric system, while another will crank out figures that would give Albert
Einstein an embolism. The following information allows you to sort through
the numbers game to come up with information that you can actually understand
and use to your best advantage.
1000 cubic centimeters = 1 liter
1 liter of water = 1 kilogram in weight
1 cubic foot of water = 6.23 imperial gallons
1 imperial gallon of water = 10 pounds in weight
1 U.S. gallon = .8 imperial gallons
1 imperial gallon = 4.55 liters
Water hardness
Appendix: Tank Figures and Facts
1 English degree of hardness = 14.3 ppm (parts per million) of calcium
carbonate
1 French degree of hardness = 10.0 ppm of calcium carbonate
1 American degree of hardness = 17.1 ppm of calcium carbonate
1 German degree of hardness = 17.9 ppm of calcium oxide
One liter = 0.26 gallons
One gallon = 3.78 liters
1 inch = 2.54 centimeters
One foot = 30 centimeters
One yard = 36 inches
One meter = 39.4 inches
Once ounce = 29 grams
To convert centimeters to inches, multiply by 0.40
To convert inches to centimeters, multiply by 2.54
To convert kilograms to pounds, multiply by 2.2
To convert pounds to kilograms, multiply by 0.453
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