Watts Water has a media called One Flow, this is a salt free media used for control of water hardness. The media does not remove the hardness but prevents Ca and Mg salts from forming scale.
This is a marketing gimic. They are bending the truth by stating this. By dictionary definition soft water is water that has had the calcium and magnesium removed. Saltless water softeners are water conditioners. They are very effective at preventing scale build up, but the water would still test hard. Polyphosfate coating is a very good option for water conditioning, but this will ONLY prevent scale build up.