What Does a Water Softener Do?
Water softeners use an ion exchange process to remove hardness minerals from your water. They use a mineral tank, brine solution, and control valve.
Over time the resin beads fill with calcium and magnesium molecules. A normal backwash cycle or a controlled regeneration cycles re-cleans the beads and recharges the system.
Ion exchange
The ion exchange process is what makes a water softener work. During this process, hardness minerals like calcium and magnesium are swapped with sodium ions from the salt that is used in your softener. This is done within the resin tank of your softener system. Ion exchange is a common water treatment technique and is effective in reducing the amount of minerals in your water. However, it does not remove contaminants that are not cations. For instance, arsenic and selenite will not be removed from your water.
Water enters the resin bed of your water softener through a discharge line and percolates through sand-like beads. The resin beads have a negative electric charge that attracts the positively charged magnesium and calcium ions in your water. The ions bind with the resin and are flushed through the drain. After the resin bed is saturated with ions, it must be recharged or regenerated. This is done by running a brine solution through the tank. The salt ions in the brine solution are exchanged with the calcium and magnesium ions on the resin and the excess ions are flushed down the drain.
This process does release a small amount of sodium into your softened water, but it is not as much as many people think. In fact, a cup of softened water contains about 37 milligrams of sodium, which is less than one slice of white bread or 2% of the recommended daily sodium intake.
Removing calcium and magnesium
Water softeners reduce the negative effects of hardness minerals on household plumbing and appliances by replacing the calcium and magnesium ions in your home’s water Whole house stainless steel water purifier with sodium ions. This simple but effective technique makes spotty dishes and dry skin a thing of the past, while preventing scale buildup in pipes and extending the life of washers and dryers.
Most modern residential water softeners use the ion exchange process to manage hardness minerals. As the water passes through the softener’s ion exchange resin tank, the calcium and magnesium ions are swapped for tiny sodium ions. The resulting soft water can then be used throughout the home.
Eventually the ion exchange resin in the water softener will become saturated with hardness minerals and stop working efficiently. To recharge the resin, it is backwashed with a salt brine solution (see NebGuide EC703 Drinking Water: Treatment).
Other types of water softeners exist that do not require ion exchange. One of these is a magnetic water softener which works by neutralizing the positive charges in hardness minerals. They do not remove the mineral deposits but simply transform them into micro-crystals that cannot bond with surfaces and produce scale buildup. Another type of non-chemical water softening system is called template assisted crystallization or TAC. These systems convert dissolved calcium and magnesium into micro-crystals that cannot stick to surfaces, but they do not prevent pre-existing scale buildup or improve the effectiveness of detergents and soaps.
Removing iron
Iron is one of the most common contaminants found in residential water. It can clog pipes, affect the taste of tea and coffee, and leave bright-colored stains on appliances in concentrations as low as 3 ppm (parts-per-million). Water testing Commercial Water Filter is an important first step to determining if you have iron present in your water supply and if a water softener will help reduce it.
A water softener removes hardness minerals through a process called ion exchange, which involves passing the water through a bed of spherical resin beads. The resin has a negative charge, making it anions while the calcium and magnesium minerals have a positive charge, which makes them cations. Since opposite charges attract, the resin beads seize onto the mineral ions and eject them from the water. The ejected ions are deposited in the salt tank for future regeneration.
The typical regeneration sequence in a water softener does not effectively remove organic iron, so the resin bed will often become “iron bound.” The iron stays embedded in the resin and can lead to high pressure loss or short circuiting of the resin. Iron-bound resin beds require frequent cleaning and may need replacement.
Using “iron out” salt will help prevent this problem and will also lengthen the life of your water softener’s resin bed. However, if you have excessive amounts of iron in your water, a more comprehensive water filtration system is the best choice.
Adding salt
Water softeners are a great investment, but they do require regular maintenance. Having enough salt in your brine tank is essential for the proper functioning of your system. Without it, your resin beads wouldn’t regenerate and hard minerals would pass through the system unchecked, resulting in unsightly stains on dishes and fixtures as well as mineral buildup in your pipes.
The type of salt you use to fill your brine tank also makes a difference. While rock salt, ion exchange, and sea salt are all suitable for water softening, evaporated sea salt is the most effective option because it is more pure and dissolves better. However, it is typically more expensive.
Your family’s water consumption is another factor to consider when determining how often to add salt. A large family will consume more water and need to refill the tank more frequently than a small family.
When checking the salt level in your brine tank, it is important to check for salt bridges, which are hard crusty layers that prevent water from mixing with the salt, preventing regeneration. You should also look for a layer of salt mush that doesn’t dissolve and can clog the tank. Be sure to clean your brine tank annually or as recommended by the manufacturer. Lastly, be careful not to overfill the tank; this can cause problems.