Introduction

• Water typically is harvested from underground sources to provide the water you use for drinking, showering, or watering your lawn. However, as this water moves through the dirt and rocks of the earth, it can pick up traces of minerals such as magnesium or calcium. An overabundance of these minerals in a water system is considered "hard" water. To treat this problem, many home owners choose to use a water softener. An ion softener works through a process called an ion exchange.
  
  

Beads

• Inside a water softening tank are many polystyrene beads, often referred to as zeolite. These beads are made in such a way that they possess a negative charge. As hard water enters the softening tank, it is forced through the beads, causing an ion exchange.
  
  

Charges

• An ion exchange occurs because of the positive charge of the calcium and magnesium interacting with the negative charge of the polystyrene beads. Since opposite charges attract, as the water passes through the beads, the calcium and magnesium will stick to beads, leaving the filtered and softened water to travel out of the tank.
  
  

Regeneration

• Since the beads can only hold so much of the minerals, the tank must periodically be regenerated or "flushed." This is done using a brine solution of sodium and water. As the brine solution is pumped into the tank, the calcium and magnesium deposits are forced off of the beads and replaced by the sodium. Even though calcium and magnesium have a higher positive charge than sodium (and therefore have a better chance of remaining on the beads), the sheer force with which the sodium is propelled at the beads is enough to dislodge the other minerals from the beads' surface, leaving only sodium remaining. Once the new hard water is introduced into the tank, the higher positive charge of the minerals displaces the sodium from the beads, allowing the process to start all over again.