The answer to 'types of water softener' is there are several main types of water softeners to choose from for your home. The most common types are salt-based ion exchange softeners, salt-free water conditioners, and reverse osmosis systems.
Salt-based ion exchange softeners work by removing hardness minerals like calcium and magnesium from the water and replacing them with sodium ions. This is the most effective way to soften water, but it does require regular salt refills. Salt-free conditioners use a process called template-assisted crystallization to alter the hardness minerals instead of removing them, which can be a more environmentally-friendly option. Reverse osmosis systems filter out a wide range of contaminants including hardness, but they produce waste water and require more maintenance.