Salt-Based vs. Salt-Free Water Softeners [Water Conditioners]

In this blog, we go over the key differences for salt-free and salt-based water softeners and go over these key takeaways:

• Salt-free softeners do not actually remove calcium or magnesium from water; they modify the calcium to limit scale formation, making them technically water conditioners.
• Salt-based softeners use ion exchange to completely remove calcium and magnesium from water, preventing scale formation.
• Salt-free water Conditioners are a better option for those who have Environmental Concerns, or households with primarily copper or metal piping
• Salt Based Water Softeners are better for those looking to remove scale on appliances, health and beauty benefits and total calcium and magnesium removal 

Similarities Between Salt-Free and Salt Based Water Softeners

Both salt free “softeners” and salt based softeners are pretreatment equipment for water. That’s about the only thing they share in common in terms of their operational purpose.

While the mechanics behind each one’s “softening” process varies bigtime, both are intended to minimize the negative impact of calcium hardness scale within your home’s appliances, piping and glass shower doors. 

Differences Between Salt-Free and Salt-Based Water Softeners

Over the years, companies have been somewhat misleading by using the term salt-free softeners. I’m sure they argue that using the term “softener” when describing their salt free product is just a matter of semantics. In reality, a salt free softener and a salt based softener are both quite different. 

The term “soft water” is water containing less than one grain per gallon of calcium. For those unaware of what a grain of calcium is, 1 grain of calcium is equal to 17.1 mg/L (milligrams per liter). In empirical measurements, 17.1 mg/L is the same as saying 17.1 pounds of calcium per million gallons of water. 

The meaning of soft water is important to highlight because a water softener, by definition, would function as a device that’s able to produce water that has a concentration of calcium less than 1 grain or 17.1 mg/L or ppm. 

How Does A Salt Based Water Softener Work?

A salt based water softener utilizes a process called ion exchange to remove calcium and magnesium from a water source. Inside a water softener, a bed of cationic resin is present. 

If you were to cut open a water softener tank, in the bottom you would see tiny orange beads about the size of the ball in a ball point pen. Under a microscope, the resin beads look like tiny balls of yarn, which increases their surface area so more ions can cling to them. 

As water passes through the resin, calcium and magnesium are exchanged for sodium ions and the effluent water is now by definition soft. 

With a salt based softener system, once the resin bed is saturated with calcium, regenerating the resin with concentrated sodium or potassium chloride brine water is required to effectively scrub the calcium ions from the resin surfaces before being placed back into service. 

How Does A Salt-Free Water Softener Work?

On the other hand we have salt free softeners, which I have already mentioned is misleading because they don’t actually remove calcium or magnesium from the effluent water at all. 

In fact, there’s the same amount of both calcium and magnesium entering a salt free water softener as there is leaving it. Within salt based softener system tanks lies a bed of polymer beads, similar to shape and size as the resin found in salt based softeners. 

Under a microscope rather than appearing like a ball of yarn, their polymer beads look like a pickleball.  As calcium and magnesium enter the bed of polymer beads, the calcium and magnesium ions are attracted to the polymer bead. 

As water continues to enter the polymer bed, the calcium and magnesium build up on the bead’s exterior to the point both ions crystallize. 

The newly formed calcium and magnesium crystals then detach from the polymer bead and exits the salt free softener. At no point during a salt free softener’s operation does it require regeneration. 

What Softening System Is Right For you?

What are the Benefits of Salt-Free Softeners?

• Salt free water softeners do not require the addition of salt at any point during their operation. 
• Virtually no maintenance required for operation. Set it and forget it!
• No cost associated with ongoing salt additions. 
• Safe to use for those living in areas that have sodium or chloride restrictions. 
• Had a relatively small footprint. 
• Electrical power supply is not needed. 
• Maintains the presence of beneficial minerals. 

What are the Benefits of Salt-Based Softeners?

• Salt based water softeners are a tried and true method for complete calcium and magnesium removal. 
• Eliminates concerns with scale buildup within appliances, water heaters and keeps glass and dishes free from calcium spotting. 
• Salt required for regeneration is relatively low at $8 per 40lb bag. 
• Salt based softeners are the ideal equipment ahead of other high purity filters like reverse osmosis and mixed bed deionization filters where eliminating calcium and magnesium is required. 
• By nature it acts as an iron filter in addition to producing soft water. 
• Healthier skin and hair as a result of complete removal of debris and soaps. 
• The use of soaps and detergents are reduced by 50-75%. 
• Salt based softeners lead to softer and overall better feeling clothes and linens. 

What are the Disadvantages of Salt Free Systems?

• Salt free systems must be sized properly to prevent undersized systems from having the proper contact time for calcium and magnesium crystallization to occur. 
• Calcium carbonate mineral buildup is not guaranteed to be prevented and it is not uncommon to still have deposit formation even after installation, especially in appliances that are heating water. 
• Should not be used ahead of other high purity water systems that require the elimination of calcium and magnesium such as reverse osmosis and deionization filters. 
• Does not provide the same health benefits to skin and hair as salt based systems that completely remove calcium and magnesium. 
• Does not provide cost savings through the reduction in soap and detergent use. 

What are the Disadvantages of Salt Based Systems?

• Ongoing maintenance is required to ensure the brine tank has the appropriate amount of salt. 
• During the softener regeneration process, highly concentrated brine water is diverted out of the softener and down the drain so these systems may not be allowed by your local governing body. 
• Must be sized properly to ensure capacity of the softener meets or exceeds your anticipated water flow rates. 
• Makeup water mineral profile is needed. 
• Most salt based softener systems require 120v electrical supply to power the softeners controller and valve operation. 
• Whole house systems should be avoided if metal plumbing is present i.e copper, iron, lead. 
• The need for a brine tank increases the footprint of the salt based softener system. 
• Calcium and magnesium will be removed from the water so some of these healthy minerals and their benefits will be forgone. 

Summary

• Soft water is water that contains less than 1 grain or 17.1 mg/l of calcium. 
• A salt free softener does NOT remove calcium from the water, it only modifies the calcium present in the water to limit its ability to bind with carbonate to form calcium carbonate scale. Making it technically classified as a water conditioner. 
• A salt based softener system removes calcium and magnesium from water through an ion exchange process which completely eliminates the ability for calcium carbonate deposits aka scale from forming. 
• Salt based systems require ongoing salt additions. 
• Salt based systems provide cost savings through the reduction of soap and detergent use by as much as 50-75%, while salt free softeners do not. 
• Most important aspect for smooth operation of either system is properly sizing the system for your use, your incoming water quality and anticipated maximum water flow rates. 

Final thoughts 

Each piece of equipment serves a purpose. For salt based softener systems, you get the entire package with the water quality it produces, with having to add salt being the most noted inconvenience. The frequency of the need to add salt can be overcome through increasing the size of the brine tank, so this is an issue that can be prevented ahead of time as long as there is room for a larger tank. This type of system may be a no-brainer for individuals that want it all and are not concerned with the cost or labor associated with occasionally adding a bag or two of salt to the brine tank each month. If you are only interested in delaying the formation of calcium carbonate in your plumbing and appliances and potentially ease the elbow grease required to clean calcium carbonate scale then a salt free system might be right for you. Think about what you are really looking for, weight the pros and cons and see what’s right for you!