Not all ice melt is the same. The bag at the hardware store might say “ice melt” on the front and tell you almost nothing about what’s inside. The formula matters, both for how well it works when temperatures drop and for what it does to your driveway, your dog’s paws, and your concrete in the process. Here’s what you need to know about magnesium chloride ice melt, how it compares to rock salt and calcium chloride, and why Liquid Rubber’s ice melt formula uses it.
What Is Magnesium Chloride?
Magnesium chloride is a naturally occurring salt compound made up of magnesium and chlorine. And yes, it is technically a salt, in the same way that rock salt and calcium chloride are salts. In chemistry, a “salt” just means a compound formed from an acid and a base. It doesn’t mean it’s the same thing as the rock salt you’re trying to move away from.
What separates magnesium chloride from the others is its chemical structure and how it behaves when it makes contact with ice. It draws moisture from the air and from the surface it’s applied to, forming a brine solution that lowers the freezing point of water. The result is a fast-acting formula that gets to work on contact. Liquid Rubber Ice Melt keeps working from 15°F to -31°F (-9°C to -35°C), the range where rock salt has already given up.
How It Compares to Rock Salt (Sodium Chloride)
Rock salt is sodium chloride. It’s the cheapest and most widely used de-icer on the market, which is why it’s everywhere. The problem isn’t that it doesn’t work. It’s that it stops working when you need it most.
Rock salt starts losing effectiveness around 15°F (-9°C). Below that, it slows down significantly and eventually stops melting altogether. The water it melts doesn’t just sit there; it refreezes, often creating a slicker surface than the one you started with. That melt-and-refreeze pattern is hard on your surfaces, too. Water expands by about 9% when it freezes, so every time it seeps into concrete and refreezes, it pushes on the surface from the inside. Repeat that cycle all winter and the damage adds up to cracks and flaking.
Magnesium chloride ice melt is 70% less corrosive than rock salt, making it gentler on concrete, metal railings, and vehicle undercarriages over time. For context, that 70% mark is the same corrosion benchmark the Pacific Northwest Snowfighters, an association of transportation agencies, uses in its specifications for corrosion-inhibited de-icers. It’s also easier on paws and plants than rock salt formulas. Liquid Rubber Ice Melt is effective down to -31°F (-35°C), so it keeps working through the temperatures that send rock salt into early retirement.
What About Calcium Chloride Ice Melt?
Calcium chloride ice melt is another common de-icer, and you’ll see it on plenty of store shelves. It’s a salt compound too, made from calcium and chlorine, and it’s known for working down to very cold temperatures. Like magnesium chloride, it’s hygroscopic, so it draws in moisture and turns to brine soon after it hits the ground. It’s also exothermic, which means it gives off heat as it dissolves. You’ll find it sold on its own or blended into other ice melts, sometimes without much of a callout on the label.
That heat is where the tradeoff starts, especially if your dog walks across treated ground. Calcium chloride releases heat quickly and intensely, so on direct contact it can burn sensitive paw pads. Magnesium chloride gives off some heat too, but it’s milder and more controlled. The flakes matter as well. Calcium chloride often comes as sharp, jagged pieces that can cut paws, and if your dog licks it off, it can irritate the mouth and stomach and in some cases cause ulcers. Since many bags don’t spell out the formula, check the label. If it doesn’t say what’s inside, it may be calcium chloride or a blend that contains it.
Why Liquid Rubber Uses a Magnesium Chloride Formula
Liquid Rubber Ice Melt is a magnesium chloride formula. It’s fast-acting and keeps working at colder temperatures than rock salt. Rock salt starts losing effectiveness around 15°F (-9°C), while Liquid Rubber Ice Melt is effective down to -31°F (-35°C). It’s also gentler on paws, plants, and surfaces than rock salt and calcium chloride alternatives.
Ice Melt is a granular de-icer built for driveways, walkways, and larger areas, anywhere you need to break down ice and snow that’s already formed.
Rock salt might be the default. It doesn’t have to be yours.
Planning ahead? Liquid Ice Melt is also available as a pre-treatment you apply before a storm to stop ice from bonding to your surface. It’s effective down to -85°F (-65°C). If you're not sure about the difference, check out our deep dive comparing Liquid Ice Melt with Ice Melt (granular).
