Seawater contains a fair amount of calcium and magnesium. In practice, does making soap with seawater or sea salt lead to more soap scum compared with “unsalted soap”? I have been using sea salt in some of my soaps without taking the complex mineral content into consideration. It dawned on me this past weekend that the various minerals might contribute to DOS. The concentrations of metals, like copper, zinc, aluminum and iron, are very, very low in seawater, so maybe it’s not a problem? In practice, has anyone noticed a tendency towards more DOS in soap made with seawater or sea salt? I would like to make some salt bars with sea salt I have on hand, but not if I’m going to have DOS problems down the road.