Re: Salinity to Conductivity conversion
Kaitlyn & Ben
The formulas in post #6 apply only to "sea salt." Sea salt is dominated by NaCl, but a lot of other ions. However, the oceans are pretty well mixed and the salt composition of real sea salt is pretty similar everywhere and close to the assumed "standard sea salt." What varies is the concentration vs fresh water added by rivers, or in areas of high evaporation, stronger than normal concentrations.
The UNESCO formulas in post #6 are only intended for varying concentrations of normal sea salt. The extension to mineral content in fresh water by USGS is probably dubious, but better than nothing. The ions making up the mineral content in "fresh water" are much more variable depending on what the fresh water runs through.
There is not a lot of KCl in sea salt. KCl is only used for calibration of the appartus. (I don't know the background. Maybe it is in the 140 page UNESCO document. I only skimmed it looking for the algorithm.)