pH = -log[H+] ..... [H+] is the concentration of hydrogen ions (= protons) measured in Eq/l (that's equivalents <number of charge, or in H+ = number of molecules> per liter) .... pH itself has no units.
is a measurment of the HCO3
concentration ... this is measured in mg
/l <milligrams per liters> which is the same as ppm
is also measured in degrees hardness (dH) -- 1mg/l = 0.056 dH. Note that the dH is US measure, there is also German degrees & grains (British?) hardness. You can also convert ppm
to mEq/l. For CaCO3
, 1mg/l = 0.02 mEq/l.
Picky technical note - typical KH
kits do not measure KH
! The kits actually measures total alkalinity, although the unit is expressed as the equivalent KH
. (ie dKH
are all measured in mg
). You can covert to mEq/l by dividing ppm
by the respective molecular weight then multiply by the number of charge of the molecule.
Specific gravity has no unit. This is a measure of density as a ratio to pure water.
Water's density = 1g/ml or 1Kg/l
if you add (say) 10 g of salt to 1l of water, the density of that salt water is (1000g + 10 g)/l or 1.010 Kg/l.
specific gravity = density of salt water /density of water ....
in this example sg
= 1.010 Kg/l / 1.000 Kg/l = 1.010 .....
ie. to get specific gravity, you just calculate the density in Kg/l & drop the units!