1. Bulk unit: Liter (the bulk unit of measurement that L) is international standard, one liter is equal to one thousandth stere. We also regard the bulk of aquatic animals box as unit of measurement with liter normally, if use centimeter (Cm) regards length as the unit, = of common volume of case of quadrate aquatic animals grows tall ÷ of × wide × 1000, and 3.14 ÷ of × of height of water level of × of radius of × of radius of = of volume of case of cylindroid aquatic animals 1000, the result that reach is the liter number of aquatic animals box namely. General one liter fresh water has 1 kilogram to weigh about, seawater is weighed slightly a bit, cursory nevertheless consideration is OK also 1 kilogram plan.

In medicaments in using, we use smaller bulk unit normally- - milliliter (Ml) , 1 milliliter is equal to one thousandth litres. Still have a kind of rough calculation method: Natural and drippy water is 1 milliliter about 18 drops, 18 drug dripping in past aquarium that is to say is 1 milliliter about.

Drug of additionally a few entrances and equipment still use the unit that exports a nation, common is gallon (GALLON) and ounce (OUNCE) . Gallon has again imperial with US-made cent, imperial 1 gallon is equal to 4.546 liter, US-made 1 gallon is equal to 3.785 liter, should notice to distinguish. Ounce is not bulk unit actually, however maund, 1 ounce approximates 28.35 grams, some manufacturers like to make the unit of measurement of drug with it.

2. Chroma unit: The metropolis in a lot of piscicultural reference book uses the densimeter that this chroma unit regards Ppm as medicaments to measure, ppm is the abbreviate of English Part Per Million, meaning for " hundred... " . Milligram says first here (the concept of Mg) , 1 milligram is equal to one thousandth gram. 1ppm is equivalent to joining the chroma of the medicaments of 1 milligram in one liter water, namely 1ppm=1 milligram / liter, with this analogize, 100 milligram are joined in the water system of 100 liter namely the medicaments of 0.1 grams, chroma is 1ppm namely.