Some critics have called the no salt water softening system a scam, partially because of the many dubious claims made by the manufacturers. These systems aren’t capable of removing minerals, such as calcium and magnesium, which is necessary to truly “soften” water. These no salt systems simply try to break down the hardness in the water, with little to no efficient outcome.
Independent studies have shown that salt-free water softeners are not as effective as a traditional salt-based water softener. When both salt-based and salt-free systems were tested in clinical trials, it was found that the salt-free system had very little to no effect on the chemical and physical composition of the water. It was further shown that these salt-free systems were unable to reduce mineral deposits left in water pipes and faucets. Salt-free systems were unable to rid water of any type on iron or manganese that may or may not be in the water as well.
The traditional salt-based water softener is still the one to rely on for great overall performance and cost-effectiveness.