The Best Pool Salt You Should Use and Why
The best pool salt is designed specifically for pools because it’s coarser and comes in large 40-pound bags. Here’s the brand I recommend (it might look familiar).
Professional Pool Salt crystallizes early to match the fastest dissolve rates on the market - no more waiting for hours for chlorine tablets to dissolve and produce beautiful clean water.
If you’ve joined the millions of homeowners who have built or switched to salt water pools, you know the benefits you’re getting. Softer hair and skin, clear, non-itchy eyes, and a smaller pool chemical bill.
But before you head to your local grocery store to buy a pallet of table salt, you may want to learn a little about pool salt, what it does, and what type to use in your pool.
If you don’t have a saltwater pool, but are thinking of converting, check out our article on converting to a salt water pool. And if you already have a saltwater pool, I think you’ll love our complete guide to salt water pool maintenance.
What is Pool Salt?
Pool salt is the same as table salt. It is technically and chemically the same salt you buy to sprinkle on your fries (or chips). The main ingredient is sodium chloride (NaCl). But unlike the classic Morton table salt, it doesn’t contain iodine or anti-caking agents (which stop clumping).
But the salt you buy for your pool is called pool salt for two main reasons: it’s a coarser grind that works better for saltwater chlorine generators (SWG), and you can buy it in bulk (40-pound bags), which saves you money.
How Pool Salt Turns to Chlorine?
The salt in the water passes through a saltwater chlorine generator (or SWG for short). Inside this device are titanium plates that “zap” the salt into chlorine. That’s the simplest way to explain it.
Technically, SWGs use electrolysis to split the sodium chloride (NaCl) into hypochlorous acid/hypochlorite and sodium.
You might be thinking, won’t this make the pool water taste salty? And you’d be surprised to learn that it really doesn’t. Plus, don’t taste pool water.
A saltwater chlorine generator only needs about 2,700 to 3,400 ppm (parts per million). That sounds like a lot, but the ocean has about 35,000 ppm for comparison. I built a calculator below that you can use to figure out how much salt your pool needs.
Pool Salt Calculator
Enter your pool volume and current salt reading. You’ll see exactly how much salt to add, and how many bags that works out to.
Get exact doses in The Pool Care App
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Most salt systems run between 2,700 and 3,600 ppm. Too low and the cell stops producing chlorine; too high and it can throw a fault or corrode metal fittings.
The Three Types of Pool Salt
We know a ton of salt varieties are available out there. Kosher salt, Himalayan salt, and Epsom salt to name a few. But you should really only use one of the three types of salt in your pool.
The difference between the kinds of pool salt you can buy doesn’t really have anything to do with the salt itself. All three types are salt. It has to do with how they’re acquired and produced, which can affect the price and effectiveness.
Solar Salt
Solar salt is so named because it’s the sun that helps produce it. Seawater is placed in an open holding area where it’s constantly exposed to the sun and wind. As the seawater evaporates, it leaves behind salt. This is one of the less expensive ways to produce salt because it relies on nature to do the work.
The downside is that seawater contains a lot of bacteria that can not only survive but thrive in salty conditions. It also has millions of teeny tiny brine shrimp in it. Despite their size, they’re still an impurity in the salt remaining from the evaporated seawater. And the more water that evaporates, the more the brine shrimp thrive in the salty environment.
Sadly, as the evaporation process continues, the salt level becomes so high that it kills all the little brine shrimp. So now instead of just shrimp in your pool salt, you have millions of tiny shrimp carcasses. We’re not quite sure one is really better than the other.
The good news is, the high-salt environment eventually kills the bacteria as well. But now you have even more organic impurities in your pool salt.
The reasons you use sanitizer and have a pool filter are to kill and remove these very types of contaminants. So it doesn’t really make sense to add them and force your chlorinator and filter to work even harder than usual, does it?
Verdict: Solar salt isn’t the best option.
Mechanically Evaporated Salt
This process is similar to the one that creates solar salt, only it uses artificially generated heat instead of the sun. Because the level of heat can be controlled, and thereby increased, it kills off the brine shrimp and bacteria at a faster rate, and rids the water of other organic impurities as well.
The bad news is, it still leaves some impurities in the pool salt, mainly in the form of minerals, including:
- Magnesium
- Calcium (which could have an effect on the calcium hardness in your pool)
- Copper (which can stain your pool unless you use a metal sequestrant)
- Iron (ditto what copper does)
- Nitrates
- Silicates
- Phosphates (though we don’t count pool phosphates as something to get rid of)
The type and number of minerals that remain after mechanical evaporation depend on where the water came from. While they don’t have the gross-out factor of bacteria and dead shrimp, they can still wreak havoc with your ability to keep your water chemically balanced.
In addition, some minerals like calcium can also have a negative effect on your pool, chlorinator, and other equipment. So again, your filter will have to work overtime to clean the water, and you’ll have to clean your filter more often.
Verdict: Mechanically evaporated pool salt can be OK. But it’s probably going to make more work for you.
Mined Salt
This is exactly what it sounds like—salt that comes from mines. This is where rock salt comes from, like cloudy diamonds pulled from the earth. In the United States, rock salt is the most common type we use, for everything from dining tables to icy roads to swimming pools.
Rock salt is the purest type of pool salt you can buy, ranging from 95% to 99% sodium chloride.
Verdict: We have a winner! The good thing is, you won’t have to worry about which type of salt you’re using if you buy bags of pool salt. It’s most likely extracted from mines and is the purest you’ll find for your pool.
Hey, we’re the last ones who’re gonna tell you to tone down the saltiness. We kinda like it like that around here. But seriously, when it comes to your pool, salty is the way to go.
Just be sure to buy salt that’s labeled “pool salt” so you know it’s pure, the right size for your chlorinator, and the easier, less expensive option.
