A water softening system is a device primarily designed to reduce or remove minerals dissolved in hard water such as calcium, magnesium and metal iron. This is because these minerals tend to stick on water and pipe surfaces leading to restriction of water flow in pipes.
In order to get rid of hard water ions, there are two major types of water softening systems: salt-base and salt-free.
Salt-Based Water Softener
This system utilizes salt as a means of getting rid of ions that cause water hardness in a process known as ‘Ion exchange’. Their structure is made of two separate tanks; resin tank and brine tank.
The resin tank is made of a resin bed whose function is to pull ions (calcium and magnesium) from hard water passing through the tank.
Brine tank contains brine solution (sodium and salt) flushed through the resin tank to drive off calcium and magnesium ions from the already saturated resin beads. Sodium ions replace the hard ions while salt cleans the resin bed through a process known as regeneration.
Example: The Fleck 5600SXT
Salt-Free Water Softener
This system utilizes the descaling method in order to condition hard water while retaining hard water minerals.
Descaling is a process that involves alteration of the molecular structure of calcium and magnesium ions to prevent them from sticking to the interior of water sources.
In this process, these hard ions (calcium and magnesium) undergo crystallization through a course known as Template Assisted Crystallization (TAC) by use of a catalytic media. During this process, calcium and magnesium minerals undergo electrical charging and transform into hard crystals, which prevents them from binding into surfaces.
Salt-Based & Salt-Free Water Softener Comparison
Salt-based water softeners remove hard water ions through the ‘Ion exchange’ method by replacing calcium and magnesium ions with sodium ions using a polymer resin bed.
Salt-free water softeners DO NOT remove hard water ions. However, they alter the chemical structure of hard water ions into hard crystals in order to prevent them from sticking on pipe surfaces and water sources.
Electronic Metered Valve
An electronic metered valve is a device mounted on top of a fiberglass resin tank. Its function is to meter water in terms of gallons and create a series of backflush cycles that clean up the resin bed when it is at its point of saturation. The process known as regeneration.
Salt-based water softeners utilize an electronic metered valve. Its function is to carry out a series of backflushes in the resin tank during the cleaning cycles. This allows the system to get rid of hard water ions trapped by the system and flush wastewater down the drainpipes.
Salt-free systems do not use electronic metered valve since they condition hard water instead of removing the hard minerals (calcium and magnesium ions). Hence, the system does not need to purge hard water ions or go through a cleaning cycle since they do not have a resin tank.
Water Softener Aesthetics
With a salt-based water softener, you no longer have to deal with scale build-up that tends to stick on every water pipe and faucet. Even your plumbing system will be thankful. This is because soft ions replace hard water ions and wastewater gets drained through drainage pipes.
However, when it comes to prevention of limescale build-up, salt-free systems are not as effective. This is due to the presence of elements that cause scale build-up since salt-free systems do not remove hard ions but rather crystallize them, which apparently is not very effective.
If you loathe the idea of using chemicals to solve hard water issues, a salt-free water softener is ideal for you. This is because the system does not remove hard water minerals but rather crystalize them to prevent them from adhering on water sources’ surfaces. In addition, calcium and magnesium have health benefits too.
Salt-based water systems replace hard water ions with sodium and use salt pellets to regenerate. These high sodium levels in water are harmful to human health especially people on low salt diets. Soft water is also demineralized.
Water hardness level
Salt-based water softeners are more effective when it comes to very hard water levels above 15gpg while salt-free water softeners are more efficient at a low and medium level of water hardness.
The level of hardness in water is measured in grain per gallon (gpg). Salt-based water test done before water treatment at 10 grains per gallon would read 0 grain per gallon after water treatment. This means that the system is very efficient.
On the other hand, salt-free water hardness done before treatment at 10 grains per gallon would yield 10 grain per gallon after water is treated. This is because of the presence of hard ions. Hence, a salt-based system is more efficient when exposed to low water hardness levels.
Salt-free systems are slower in comparison to salt-based systems in respect to time taken to deliver results. Salt-based systems use a filtration method, which starts at the water source immediately after you start drawing and using water. However, salt-free systems use electricity hence delays the results of water treated by the softener.
How To Maintain Your Water Softener
- Rock salt is cheaper than pelleted salt. However, rock salt contains high levels of calcium sulfate, which unfortunately cannot dissolve in water and settles in the brine tank in the form of a sediment mush. To avoid this, use pelleted salt.
- If your system produces a pungent smell, it is mainly due to the presence of Sulphur bacteria. You can solve this issue by use of bleach or simply follow the owners’ manual.
- If the brine tank blocks due to a heavy block of salt, you can pour warm water over the salt and loosen it immediately.
Functions Of Salt In a Salt-Based Unit
Salt is a regenerating agent in salt-based systems. When the resin bed reaches its saturation point, salt-based water softeners use salt to wash off calcium and magnesium ions from the resin bed into the wastewater system.
Next, they substitute them with sodium chloride ions by means of a series of back flushes known as regeneration. This creates room in the resin tank to allow for more hard water purification.
It is advisable to purchase salt made specifically for water softening.
Salt-based water softeners can operate with potassium chloride as a substitute in place of the salt, sodium chloride. However, potassium chloride tends to be pocket unfriendly than salt and can be a hard-to-find item depending on the shopping options in your location.
Experts, however, recommend an increase of the salt control setting when using potassium chloride as a substitute although this might lead to additional expenses.
Using Potassium chloride can turn out to be quiet an expensive affair. But, it is worth noting that this metal halide is composed of potassium and chloride minerals, which do not add salt to the softening process.
Therefore, this is a healthy option, especially if you are on a low sodium diet.
If you are dealing with a lot of limescale formation on your bathroom, water equipment surfaces and your skin feels dry and raspy, you should go for the salt-based water softeners.
However, if what you are looking for is a low maintenance, chemical-free softener unit, consider the salt-free water softener.
It is worth knowing that salt-free water conditioners will not decrease your detergent or soap usage. They don’t make your clothes whiter and brighter. So, the annoying spots will not be eliminated nor will they give your clothes they soft feeling you desire.
If you want to avoid scales forming in and around your water surfaces, opt for the salt-based water softener, which guarantees soft water.
The downside of salt-based systems is that they waste a lot of water regenerating the system. In addition, it is advisable to avoid drinking water directly from the system unless you have a filter.
In conclusion, between the two systems, none is healthy for direct drinking and at the same time gets rid of scale build-up here and there.
Therefore, as a buyer, it is up to you to choose a water softener that leaves sparkle here and there but has high levels of sodium concentration and fewer minerals. Or, alternatively, choose a system that allows you to enjoy mineral water direct from your faucets but limits you to dealing with scale formation in water surfaces.
Jake is a clean water enthusiast and blogger. He has spent his university days in Chicago studying various water filtration technologies and now enjoys helping people live healthier lives when it comes to water consumption.