TAC vs NAC Media Explained

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Template-assisted crystallization (TAC for short) and nucleation-assisted crystallization (NAC) are two very similar salt-free water conditioning processes. If you’re considering a salt-free water softener, there’s a good chance that the system uses one of the two conditioning techniques.

Do template-assisted crystallization and nucleation-assisted crystallization work? The answer is yes, both technologies can be used to condition your water – and this article will explain the science behind these processes, and how they prevent scale formation in hard water.

🚰 What is Salt-Free Water Conditioning?

Salt-free water conditioning is classed as a water softening process, but water isn’t technically softened using this method.

To understand how a water conditioner works, let’s first look at the traditional salt-based ion exchange water softening process. Calcium and magnesium, the two minerals that are responsible for scale, are completely removed in ion exchange water softeners.

During the ion exchange process, these hardness minerals are attracted to a softening resin, which contains sodium ions. When the hardness ions stick to this resin, they’re exchanged for sodium ions, which are released into water to balance out its charge. After this process is complete, water is classed as soft, because it no longer contains the minerals that cause scale.

Ion exchange water softeners provide water softening, while water salt-free conditioners provide water conditioning. Both methods result in scale prevention, but salt-free conditioning units don’t remove calcium and magnesium from water.

Salt free water softener diagram
How a Salt-Free Water Softener Works

Instead, water conditioners alter the formation of hard water minerals, preventing them from being able to form scale. TAC, NAC, and several other, less popular methods of conditioning can be used in place of ion-exchange softeners or water filter systems that can remove hard water ions, like reverse osmosis.

When used for conditioning purposes in residential applications, salt-free water softeners have several advantages over traditional water softeners, including:

  • A salt-free water softener is the more environmentally-friendly option because the system doesn’t waste water or regenerate – two essential requirements for salt-based water softeners.
  • Additionally, salt-free water softeners don’t need salt, which helps you save money, reduces the frequency of maintenance, and is the better choice for people on a low-sodium diet.
  • Finally, salt-free conditioning systems don’t actually remove hardness ions, despite preventing limescale formation. This means you can still enjoy the healthy natural mineral quantity in your water, which gives water a pleasant mineral taste.

The below sections provide more information about the template-assisted crystallization and nucleation-assisted crystallization processes.

🌐 What is Template Assisted Crystallization (TAC)?

Template-assisted crystallization changes the structure of calcium and magnesium minerals by having these minerals interact with a media inside the TAC conditioning chamber. How exactly does TAC water treatment work?

Template-Assisted Crystallization – The Process

A TAC media is made up of hundreds of very small polymer beads. When water flows through these beads, the calcium carbonate and magnesium ions stick to the media. Calcium and magnesium will continue to build up in the media and begin to convert into small micro-crystals.

The crystals break off from the media once they reach a certain size, flowing back into your drinking water. This happens on a consistent basis, so a measured amount of calcium and magnesium crystals are released during the conditioning water treatment process. You won’t end up with a large number of crystals in your water all at once.

Template assisted crystallization media diagram
Template-Assisted Crystallization Process

In their new crystallized form, magnesium and calcium will remain in your water as it flows through your plumbing. The minerals are unable to leave water or stick to surfaces and cause scale, so the pipes and appliances in your whole house, including your tankless water heater and other water systems, will be free from scale using this process.

TAC doesn’t actually soften water, and you’ll still technically end up with hard water, but TAC still provides all the benefits of soft water. Because the water hardness ions are unable to form scale, you won’t experience the classic hard water problems, like reduced water pressure, restricted flow rates, white spots on your dishware, and difficult-to-clean hard water scale build-up.

Some manufacturers say that template-assisted crystallization can reduce existing scale formation, but there’s little evidence to support this information.

Template-assisted crystallization costs about the same as a salt-based softener upfront, but this water treatment system is more affordable in the long term because no salt or water waste is involved. Additionally, TAC maintains your water quality, so you can still benefit from healthy minerals in your drinking water.


Installing a TAC conditioner is generally easier than installing a water softener because there’s only one tank to install, and you don’t need to connect the unit to a drain line. You should install the conditioner at your home’s point of entry, before your tankless water heater, to prevent hard water scale damage to any of the appliances in your home.


TAC technology is virtually maintenance-free, but you will need to replace the media in TAC systems eventually. Most systems have media that can last for at least 6-8 years. After this, the technology will become ineffective in crystallizing hardness ions, resulting in limescale buildup.

πŸŒ€ What is Nucleation Assisted Crystallization (NAC)?

Template-assisted crystallization and nucleation-assisted crystallization are often referred to as the same thing, or even interchangeably, and this is because the process is virtually the same for both methods of water treatment.

Nucleation-Assisted Crystallization – The Process

There’s no evidence to suggest that TAC or NAC works better, so if a salt-free water softener uses an NAC media, it’ll provide essentially the same water conditioning as a TAC conditioner.

In fact, nucleation-assisted crystallization seems to be just another name for template-assisted crystallization. The name “nucleation-assisted” refers to the nucleation sites that are provided by the media beads inside NAC conditioning tanks. Again, this media transforms magnesium and calcium into micro-crystals that are unable to adhere to surfaces and form scale.

Nucleation-assisted crystallization process
Nucleation-Assisted Crystallization Process

Like TAC, NAC releases the crystals back into the water, ensuring that water retains the same feel and pleasant alkaline taste. Sodium isn’t added to water, and the magnesium and calcium ions aren’t actually removed, so you’re still left with hard water that can’t form scale.

NAC provides scale prevention around your home, including in your tankless water heater and other appliances.


Installation of NAC water treatment systems is the same as installing a TAC system because both units consist of a single tank containing media.


NAC technology is just as cost-effective to maintain as TAC because it also doesn’t need salt, excess water, or any other regular maintenance to operate. Again, the media will need replacing after approximately 6-8 years.

In all, both of these conditioning techniques are an environmentally friendly alternative to the traditional water softening process.

  • Laura Shallcross
    Senior Editor

    Laura is a passionate residential water treatment journalist who holds an undergraduate degree in Print Journalism and a master’s degree in Creative Writing. Over a span of 5 years she's written on a range of topics including water softening, well water treatment, and purification processes.

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