The total amount of salt dissolved in Great Salt Lake is about 4.5 to 4.9 billion tons. As the lake rises, its salinity drops because the same amount of salt is dissolved in more water. The lower the lake level, the saltier the lake becomes. In historical time, the lake's salinity has ranged from a little less than 5 percent, (just above that of sea water), to nearly 27 percent (beyond which water cannot hold more salt).
You can easily float in Great Salt Lake if the water is salty enough. At the lake's average elevation of 4,200 feet, the south arm of the lake contains about 13 percent salt, which makes it salty enough for most people to float with little effort. When the lake is higher than 4,200 feet, it is less salty and therefore less buoyant. Swimmers float easily in the north arm because it is twice as salty as the south arm.
The chemical composition of Great Salt Lake is similar to that of typical ocean water. Sodium and chloride are the major ions in the water, followed by sulfate, magnesium, calcium, and potassium. For comparison, the table below shows the concentration of the six major ions in water of Great Salt Lake, a typical ocean, and the Dead Sea.
Located ca. 17 mi west of Salt Lake City at Interstate 80, Exit 104.