The Many Benefits of Salt
1.How to prevent the crystals from getting wet?

To prevent the crystals from getting wet, a free-flowing agent is needed. The compound used must possess a small particle size and be water insoluble. It may keep the crystals physically separate, like tricalcium phosphate, or actually absorb the moisture, such as the silicates. These have a higher attraction for water vapor than the salt and can absorb and give off the moisture without forming a brine. Sodium silicoaluminate is widely used as an anti-caking agent in table salt, but other types can be added, including silica dioxides and magnesium carbonate.

Salt by the sea
2.What is difference between granulated salt and sea salt?

Table or granulated salts contain about 2,400 mg of sodium per teaspoon; however, coarse grades of sea salt have fewer crystals per teaspoon and, therefore, less sodium by volume. The difference is less dramatic by weight. While a typical refined table salt is 99%-plus sodium chloride, or about 40% sodium, a typical sea salt might only have about 96% sodium chloride, somewhere in the neighborhood of 38.5% sodium. One sea-salt-based product marketed by Nexcel Natural Ingredients, a division of Spectrum Foods, Springfield, IL, is called a natural sodium-reduced, magnesium-enriched sea salt with sodium, potassium and magnesium that, the company says, "contains 60% less sodium than ordinary salt yet can be used to replace it on a 1:1 basis."