Salt Free Water Softeners - Do They Work?
Beware of the con job.
People with hard water rely on water softeners to improve their water quality. Our town has very hard water, and most homes have a salt-based water softener. In more recent years, we have seen several salt-free softeners on the market.
Do they really work?
Should you replace your salt system with a salt-free one?
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What is Hard Water?
Water contains several minerals, and when the amount of these gets too high, we call it hard water. Most of this ‘hardness” is caused by calcium and magnesium.
Hard water causes several problems:
Scale built up in pipes: This is a white deposit that forms inside pipes and valves in your water system. If enough builds up, it can plug the system and cause expensive repairs.
White deposits in tea kettles and other appliances: This is mostly an aesthetic problem.
Soaps don’t work as well: Soaps don’t lather as well and leave soap scum and spots on glassware.
Harm plants: The white deposits accumulate in potted plants, causing root problems, and a higher pH of the potting media, making it harder for plants to absorb nutrients.
Dry skin and hair: Who wants that?
These white deposits are caused mostly by calcium and magnesium carbonate salts.
While not a health risk, these deposits shorten the life of equipment and result in unsightly stains.
To understand how hard water affects plants, see Water Hardness and Alkalinity – Why They Both Matter
How is Hardness Measured?
Water hardness is measured in a couple of different ways.
Chemists generally express it in milligrams per liter (mg/L) of CaCO₃ equivalent, or parts per million (ppm) of CaCO₃ equivalent. 1 mg/L = 1 ppm.
A more popular unit used by the general public in North America is the “grains” or more correctly grains per gallon (gpg). 1 grain of harness = 17.1 ppm CaCO₃.
In the UK, they use Clark degrees, where one Clark degree = 14.3 ppm CaCO₃
General classifications:
Soft water: 0–60 ppm CaCO₃ (0-3.5 grains)
Moderately hard: 61–120 ppm CaCO₃ (3.6-7 grains)
Hard: 121–180 ppm CaCO₃ (7.1-10.5 grains)
Very hard: >180 ppm CaCO₃ (> 10.5 grains)
Water that is above 100 ppm will benefit from a water softener.
Different Types of Water Softeners
There are three basic types of water softeners for home use. Unfortunately, some have no scientific basis and simply don’t work.
Ion Exchange (Salt-Based) Water Softeners
The most traditional and effective “true” softener is the salt-based ion exchange system. This system consists of a mineral tank filled with negatively charged resin beads. These beads are full of sodium ions from the salt used in the softener.
As hard water passes through, the calcium and magnesium ions (which carry a positive charge) are attracted to the beads and replace the sodium ions. The sodium ions end up in the tap water.
The primary advantage of this type is that it physically removes calcium and magnesium from the water. The resulting water feels “slick” and produces a rich lather.
However, these systems require regular salt refills and go through a regular regeneration cycle, which flushes the resin with salt. This process wastes water, and it also adds more sodium to the wastewater stream, which ends up in streams and lakes. This is an environmental concern.
Salt-Free Water Conditioner
Salt-free systems are not water softeners because they don’t remove any calcium or magnesium.
These systems use resin beads that cause the calcium and magnesium to stick to the beads. As the amount of material increases, it forms larger deposits that fall off as microscopic crystals, which float along with the water. They don’t stick to surfaces and therefore don’t cause scaling.
Because these systems don’t use salt or electricity and produce no wastewater, they are favored by eco-conscious homeowners and those on low-sodium diets. While they are excellent at preventing scale in pipes and water heaters, they do not provide the “soft” feel of ion-exchanged water and are generally less effective in areas with high water hardness.
These conditioners are not recommended for a water hardness greater than 10 grains or 170 ppm. These units are smaller and more suitable for apartments.
Magnetic and Electronic Descalers
These are compact, “plug-and-play” devices that wrap around the main water pipe. They use magnetic or electromagnetic fields to alter the behavior of mineral particles, preventing them from adhering to plumbing. While they take up almost no space and require zero maintenance, their effectiveness is questionable.
How do they work? Numerous suggestions involving things like ionization, north-south polarity, electric pulses, and colloidal properties are mentioned, but none of these have any scientific support.
Few scientific studies: There have been few studies that have looked at their efficacy. None has found strong evidence that they work. “Magnetic water treatment, unlike the other technologies previously described, should be regarded as unproven technology without a strong scientific basis.”
The Water Quality Association: “knows of no generally recognized scientific or technical evidence which proves that magnetic, electromagnetic or catalytic devices sold to treat water have any measurable physical or chemical effect on water quality”.
No change on Chemistry of Water: Several devices I looked at claimed they don’t change the chemistry of the water, which makes no sense to me, since that would mean they don’t work.
The current science does not support the use of magnetic descalers.
There are two types of descalers on the market. Some use a permanent magnet that gets attached to the copper pipes. Others use a coil of wire or wire tape wrapped around the copper pipe.
