- The Fix
- The Brains
- Judging Water Hardness
- Health Concerns

It's easy to forget how important water is in our lives. Of course we need it in our diet, but in our homes, it's a tool-a fluid medium that carries material from one place to the next. And one of the reasons it does this job well is that it's very good at holding things, either by suspending them or dissolving them.
Unlike most tools, though, water doesn't come with an instruction manual. If it did, you'd know why the dishes you thought were washed are covered with spots when dry, why the water in your shower leaves a film on everything it touches, and why what you thought was clean water has clogged up your plumbing system.

1. The backwash phase removes dirt from the mineral tank.
2. Recharging the mineral tank with sodium from the brine solution displaces calcium and magnesium, which is then washed down the drain.
3. The final phase rinses the mineral tank with fresh water and loads the brine tank so it's ready for the next cycle.

The Fix
The solution to the problem is to get rid of the calcium and magnesium. While there are chemical treatments that do this, the most popular answer is a water softener.
The typical water softener is a mechanical appliance that's plumbed into your home's water supply system. All water softeners use the same operating principle: They trade the minerals for something else, in most cases sodium. The process is called ion exchange.
The heart of a water softener is a mineral tank. It's filled with small polystyrene beads, also known as resin or zeolite. The beads carry a negative charge.
Calcium and magnesium in water both carry positive charges. This means that these minerals will cling to the beads as the hard water passes through the mineral tank. Sodium ions also have positive charges, albeit not as strong as the charge on the calcium and magnesium. When a very strong brine solution is flushed through a tank that has beads already saturated with calcium and magnesium, the sheer volume of the sodium ions is enough to drive the calcium and magnesium ions off the beads. Water softeners have a separate brine tank that uses common salt to create this brine solution.
In normal operation, hard water moves into the mineral tank and the calcium and magnesium ions move to the beads, replacing sodium ions. The sodium ions go into the water. Once the beads are saturated with calcium and magnesium, the unit enters a 3-phase regenerating cycle. First, the backwash phase reverses water flow to flush dirt out of the tank. In the recharge phase, the concentrated sodium-rich salt solution is carried from the brine tank through the mineral tank. The sodium collects on the beads, replacing the calcium and magnesium, which go down the drain. Once this phase is over, the mineral tank is flushed of excess brine and the brine tank is refilled.
In ion exchange, hard water ions replace sodium ions on beads. Process is reversed to flush minerals away.

Health Concerns
Hard water poses no health hazard. On the other hand, the sodium that remains in softened water may be a problem for those on sodium-restricted diets. Other people simply may wish to avoid the slightly salty taste of treated water. In either case you can install a separate water dispenser that bypasses the softener. You also can use potassium chloride instead of salt, although this costs about three to four times more.