What Kind of Salt Can Be Used for Brine?

Photo courtesy Jake Groen, PolyJohn Canada

When temperatures drop, portable restroom owners search for affordable and effective salt solutions for brine. While rock salt remains popular for its budget-friendly freezing prevention features, it’s harsh on metal tanks. And what if you come across a great deal on pool salt or need an outside-of-the-box option for a quick solution?

This article breaks down the types of salt you can use for brine, including the pros and cons, the best uses for each kind of salt, and tips for mixing.

Rock Salt or Road Salt: Affordable for Brine

Rock salt and road salt are sodium chloride (NaCI) which is used for de-icing. Both are usually less expensive than alternatives, yet they are corrosive to metal tanks and valves. Rock salt is typically unrefined, meaning it’s coarse, loose, and may have some natural clay or minerals mixed in it. This can leave sediment in tanks.

Road salt is processed, so it could have additives or anti-caking agents, which makes it easier to spread, store, and handle. However, additives could affect brine performance or cause foaming in tanks. Portable restroom businesses using bulk salt and large batch containers often prefer rock salt for its affordability.

Water Softener or Solar Salt Crystals: Cleaner and Less Residue

You can use water softener salts and solar salt crystals if you’re winterizing flushing units or standard units and want an alternative to rock or road salt to avoid corrosive elements. Pool salt also works (and dissolves quickly and evenly) but usually costs more than water softener or solar salt.

When choosing between these solutions, here’s what to consider:

• Water softener salt: Best for dealing with equipment prone to clogging from residue or when you need a fast-dissolving salt. Check for additives on the label, as these could affect your tank systems.
• Solar salt: Crystals are more economical and environmentally friendly for a natural brine solution with a slower dissolve time. Although it leaves less sediment than rock salt, the larger crystals may dissolve unevenly, requiring more oversight during brine-making.

Magnesium Chloride or Ice Melt: Choose Wisely

When preparing for extreme temperatures, magnesium chloride dissolves easily in water to create a brine and is more effective at lower temperatures than rock salt, water softener, or solar salt. It’s also less corrosive than rock or road salt, with less residue. However, it costs more. On the other hand, PROs must choose wisely when using ice melt in brine.

The performance depends on the ingredients. Ice melt typically contains magnesium chloride, sodium chloride, calcium chloride, and other de-icing chemicals. If it has additives, like anti-caking agents, these can increase residue or cause foaming. Corrosiveness also varies depending on the blend.

Select the Right Kind of Salt for Brine (And Grab a Hydrometer)

Portable restroom operators spend a lot to prevent freezing during the winter. It’s about buying salt, devoting time to mixing a brine solution, and treating various tanks and equipment. If you haven’t picked up a hydrometer yet, grab one. It’s a simple tool that anyone can use to measure salt concentration, which helps you avoid overusing salt or not using enough.

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