Litmus "Lecanora tartarea" (Norway, Sweden), "Variolaria dealbata", "Ochrolechia parella", "Parmotrema tinctorum", and "Parmelia". Currently, the main sources are "Roccella montagnei" (Mozambique) and "Dendrographa leucophoea" (California). The main use of litmus is to test whether a solution is acidic or basic. Wet litmus paper can also be used to test for water-soluble gases that affect acidity or alkalinity; the gas dissolves in the water and the resulting solution colors the litmus paper. For instance, ammonia gas, which is alkaline, turn the red litmus paper blue. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or
Alkalinity + "m" + "m" + "m" - "m"". Total alkalinity is measured by adding a strong acid until all the anions listed above are converted to uncharged species. The total alkalinity is not (much) affected by temperature, pressure, or pH, though the values of individual constituents are, mostly being conversions between HCO and CO. Drever further notes that in most natural waters, all anions except HCO and CO have low concentrations. Thus carbonate alkalinity, which is equal to "m" + 2"m" is also approximately equal to the total alkalinity. Alkalinity or A measures the ability of a solution to neutralize