A salt-free water conditioner works by using a process called template-assisted crystallization (TAC) to soften hard water.

TAC uses a polymeric template material that attracts and binds the hard water minerals, such as calcium and magnesium, preventing them from forming scale on surfaces and in plumbing systems.

This process does not remove the minerals, but instead alters their physical form so they remain in solution and do not cause hardness buildup.

Salt-free conditioners are sometimes referred to as "water softeners" but they do not use salt to soften the water.

The water enters the water conditioner and flows down the distribution tube. 

The water then gets pushed up through the media to condition the hard water.

The conditioned water then exits the top of the system and out to your home. 

To get optimal water quality, a whole house carbon filter can be utilized . This whole house filter is placed prior to the salt-free water conditioner.

This is an example of a typical setup.