Conversion factors

VOLUMES

1 Imperial Gallon = 4.54 litres
1 US Gallon = 3.8 litres
1 cubic foot = 28.4 litres

WEIGHTS

1 gram = 1000mg (milligram)
1 mg (milligram) = 1000 ug (microgram)
1 mg is approx 1 ppm (part per million)
1 ug is approx 1 ppb (part per billion)

HARDNESS

1 mg/l CaCO3 = 0.1 F (degree french)
                            = 0.056 dH (degrees german)
                            = 0.0584 US grains per gallon
                            = 0.0701 Clark