Rock Salt vs. Magnesium Chloride

With winter on its way, many home and business owners are starting to make preparations for the cold weather right now.

When looking at the different ice melting products on the store shelves, though, you may find yourself wondering which is best – traditional rock salt or magnesium chloride.

Are they essentially the same thing, or do they act differently from one another? And how can you be sure which product is better suited to your needs?

Because we regularly receive inquiries like these, we’ve drafted this side-by-side comparison of rock salt vs magnesium chloride so that your questions can be answered once and for all.

Rock Salt vs Magnesium Chloride: Knowledge is Power

Too many people make the mistake of believing that all de-icers are basically the same thing. While all products on the market are capable of lowering the freezing temperature of water, however, the chemical makeup of each material impacts the way that it performs and its actual capabilities.

Both rock salt (sodium chloride) and magnesium chloride are both chlorides, but are chemically different from one another. Understanding these differences can make a big difference in your experience with using ice melt this winter.

Rock Salt

Rock salt has a lengthy history of being used in the United States and around the world. Sometimes referred to as sodium chloride, NaCL, or Halite, the material works as it is absorbed into water. The water and salt mixture (brine) has a lower freezing temperature than regular H20 making it possible to melt existing ice and discourage future formations.


Throughout the years, rock salt has proven itself time and again as a reliable and readily available product. When applied as directed, rock salt is capable of working in extremely cold temperatures, but generally performs at its best between 15-20 degrees Fahrenheit.

Because the material is so easily accessible, it is one of the most affordable ice melting products on the market. This is especially advantageous for those who are working with a budget or who need to buy de-icers in bulk.


Recently, more fuel has been added to the rock salt vs. magnesium chloride debate as concerns have arisen about the impact of rock salt on the environment. It’s important to keep in mind that these problems tend to occur when users don’t stick with manufacturer specifications.

Overspreading the material won’t improve the performance of rock salt, but can cause excess granules to wash away with melted snow and ice, coming into contact with vegetation. Excessive exposure to salt can dehydrate the plants and throw off the pH balance of the soil.

Carefully and consistently spreading the proper amount of ice can prevent this. In addition, homes with pets may want to give some consideration to working with a de-icer with a CMA coating to protect their furry friend’s paws.

Magnesium Chloride

Magnesium chloride (MgCl2) has become increasingly popular. Despite the fact that rock salt remains the most popular pick amongst de-icers, some believe that magnesium is a smarter and safer alternative to its sodium-based cousin.


Magnesium chloride is typically considered to be safer for use around plants and concrete surfaces than other products, as it poses fewer threats to the environment and corrosive qualities.

In addition to this, the ice melter is very effective and fast acting. MgCl2 is a hygroscopic de-icer, meaning that it is able to absorb moisture and form into a brine very quickly, instigating the ice melting process.

It can function in temperatures below 0 degrees Fahrenheit. When used as directed, magnesium chloride leaves very little residue behind, which is especially important in areas prone to high volumes of foot traffic. Finally, depending on the brand, some MgCl2 products are coated with CMA to provide added protection for animals and children.


The biggest thing to consider before using magnesium chloride is cost. Certain properties of the product make it slightly more expensive than traditional rock salt.

In addition, MgCl2 is only 48% active. Because it has such a high water content, it can become diluted more quickly, requiring additional applications. For larger properties, this difference in the required volume of ice melt could add up.

Final Thoughts

After reading through the breakdown of rock salt vs. magnesium chloride, it should be evident that there’s no “right” or “wrong” answer. The two products may be in the same family, but are completely different, and thus, what’s a good solution for one person may not be for the next.

Homes with smaller properties and have families and pets to consider might want to talk to an expert about using magnesium chloride. Businesses and other entities with a lot of ground to cover, on the other hand, would probably be better of buying traditional rock salt in bulk. Ultimately, the choice is yours.