How Water Softers work


Water Softeners have become an essential water treatment appliance in many australian homes. Water Softening Systems are used to soften water to avoid damage to pipelines, water heaters, dishwashers and washing machines. Hard Bore Water destroys clothing and Electricity and Gas Bills can be 25% higher for a household using borewater. Hard Water contains dissolved minerals in the form of Calcium (Ca), Magnesium (Mg), and Iron (Fe). Removal of these minerals is accomplished by softening the water through an ion exchange process using a water softener. How Water Softeners Work VIDEO

Advantages of Water Softeners:

  • Higher Quality Drinking Water
  • Prevents Hard Water Scale
  • Prevents Staining on Bathroom  Kitchen Fixtures as well as Dishes, Dishwasher, Washing Machine and Clothes
  • Significantly Reduces Soap and Cleaning Product Consumption
  • Provides Excellent Grooming & Cosmetic Benefits
  • Reduces Water Heating Costs
  • Prolongs the Life of Water Heaters, Icemakers, Dishwashers, Coffeemakers and Plumbing Fixtures.

How do Water Softeners work?

A typical water softener has four major items:

    • Resin Tank
    • Resin
    • Automatic Valve (Controller)
    • Brine or Salt Tank

Hard water flows over resin in the resin tank. Resin is in the form of tiny beads that have a special chemical property. At low concentration of sodium in typical hard water, the resin beads adsorb (combine with them) the hardness of water and replace it with an equivalent amount of sodium in water. As hardness is removed the water becomes “soft”. The resin has a fixed capacity of the amount of hardness it can remove. Once that happens the resin can no longer remove the water hardness and the resin is called “saturated” or exhausted..

Fortunately, the same resin when exposed to high sodium chloride (common salt) concentration reverses the process and adsorbs the sodium and releases the hardness. This property is utilized in regenerating the exhausted resin. This is done by temporarily stopping the softening process and exposing the resin to high salt solution from the brine tank. The entire process is controlled by the controller valve which works either on time of regeneration (normally set at 2 AM) or by a meter valve inside the controller preset to a calculated amount of water that can be softened before regeneration. After regeneration the controller rinses the resin to remove all salt not adsorbed by the resin. The entire cycle lasts less than 1 hour.

Illustration of APT Aqua Pure Water Softener in service 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,magnesium and iron 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, although 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 rock 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.

Illustration of APT Aqua Pure water softener in back-washing mode
The Control System
Most popular water softeners have an automatic regenerating system. The most basic type has an electric timer that flushes and recharges the system on a regular schedule. During recharging, soft water is not available.
A second type of control uses a computer that watches how much water is used. When enough water has passed through the mineral tank to have depleted the beads of sodium, the computer triggers regeneration. These softeners often have reserve resin capacity, so that some soft water will be available during recharging.
A third type of control uses a mechanical water meter to measure water usage and initiate recharging. The advantage of this system is that no electrical components are required and the mineral tank is only recharged when necessary. When it is equipped with two mineral tanks, softened water is always available, even when the unit is recharging.
Analysing Water Hardness
Water hardness is measured in grains per gallon (GPG) or milligrams per liter (mg/l, equivalent to parts per million, or ppm). Water up to 1 GPG (or 17.1 mg/l) is considered soft, and water from 60 to 120 GPG is considered moderately hard. A water softener’s effectiveness depends on how large the softener and how hard the incoming water is. Water over 100 GPG may need to be analysed for a suitable water softener to do the job properly, especially if iron is present.

apt aqua pure ecology image

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