You may have seen another type of salt-free softener alternative on the market: salt-free conditioners. These whole house water treatment systems look more like salt-based systems, as they have a tank that water must run in and out of for treatment.
The majority of tank-based conditioners use a process called TAC to soften water, wherein water flows through a special media that alters the composition of hard minerals and prevents them from being able to stick to surfaces. They require no salt to operate; just a media that usually lasts for around 8 years.
In comparison, an electronic water descaler system has no tanks - instead, it's installed around your existing water supply line, offering simple, no-fuss treatment. Instead of altering the composition of hard water minerals, electronic water descalers alter the behavior of these minerals, which has the same effect of preventing limescale.