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Water softener operation: here we explain how water softeners and similar water conditioners work, types of water softeners, and the basics of what water softener controls are present and what they do. How water softeners work, methods to remove minerals from home water supply.
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Conventional ion-exchange water softeners used to remove minerals from "hard" water in buildings usually use salt in an ion-exchange process, swapping in sodium ions (salt) and causing calcium and magnesium to precipitate out of the building water supply (and to collect in the water softener).
[Click to enlarge any image or table]
Definition of "hard water": Hard water is generally taken to mean water containing minerals over 121 mc (micrograms) per liter of water, or over 7 grains of hardness per gallon.
Salt in the brine tank (red arrow in our photo at left) is used to place a charge of salt molecules in the resin tank (green arrow). During a regen cycle (explained below) under control of a timer or on some systems more advanced systems that actually monitor the mineral level in the water supply.
Resin inside the water softener treatment tank (green arrow in our photo) contains salt molecules which are brought into contact with building water as it passes through the softener. The "resin" is made of tiny plastic beads of zeolite which are coated with salt or potassium ions. (Ions are molecules that have an electrical charge.)
As hard water which is to be treated flows through the resin or treatment tank (tan arrow in our photo at left) containing the salt-coated zeolite resin beads, salt molecules (NaCl) on the bead surface are "swapped" into the water displacing other mineral molecules that we're trying to remove from the water, such as Calcium (Ca or CaCO3) or Magnesium (Mg) that clog up pipes and create other problems. The Ca or Mg ions stick to the resin beads where they have replaced the NaCL.
The resulting "conditioned water" or "soft water" (blue arrow in our photo at above left) flows out of the treatment tank and into the building for use.
In sum, during that contact time as your building water passes through salty resin inside the treatment tank, the ion-exchange occurs to soften the water.
Periodically the water softener needs to recharge itself, a step which is controlled either manually by the
homeowner or run automatically by a timer built into the water softener. Usually these steps involve pumping water backwards through the water softener and to a building drain, followed by
dissolving salt tablets or crystals in a nearby holding tank and pumping the new salty water into the softener.
The salty water passing back through the treatment tank has given up some of its salt to regenerate the resin beads there and it has picked up the un-wanted calcium and magnesium that were previously removed from the building water as it passed through the same tank earlier. The water used during the regeneration cycle gallons is discharged through a drain tube into an approved destination like a drywell.
How often a water softener needs to backwash and recharge itself depends on two factors: how much water is used in the building and how hard the water is.
How much salt a water softener uses at its backwash cycle depends on the hardness of the water being processed.
Reader Question: Should water actually leave the water softener during a backwash cycle?
Never used a water softener before, went to do a backwash and regenerate. Should the water actually leave the softener and then refill because it sounds as though it wants to run but no water is leaving the tank and filling back up - Jhar1986 9/19/2012
Reply: yes. Here are the details:
The water softener backwash - regeneration cycle washes out the precipitated calcium and magnesium which have stuck to the zeolite bead surface - thus having been removed from the water supply,
The salty backwash water passing through the water softener treatment tank it also re-charges the salt in its ion exchanger - salt molecules stick to the surface of the zeolite resin beads.
Water softeners address these two variables and is regenerated or "recharged" by these means
The water softener installer sets up the water softener control to specify
Some experts suspect that many homeowners use more salt and more frequent backwashing than the water usage and hardness require.
Details about how to set or adjust the water softener controls are at SOFTENER ADJUSTMENT & CONTROLS.
Continue reading at SOFTENER ADJUSTMENT & CONTROLS or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
Question: water punp runs during softener regen cycle
(Jan 17, 2013) KT said:
Should the water pump run during the entire regeneration cycle?
If the flow rate of the water softener during the regen cycle - really the latter half of the regen cycle when salty brine is being pumpd back through the water softener and out through a drain - is greater than the capacity of your well pump then the pump cannot "get ahead" of the demand for running water and the pump will run continuously.
I would expect that in the case you describe your well pump capacity, or the flow rate of your well itself is limited and that you also see continuous pump operation when you are running a bath tub at the tub spout or are running multiple plumbing fixtures at once.
Question: life of water softener resin
(Feb 17, 2013) Eric said:
Greetings. I have a Culligan Mark 10 system and the Culligan folks came out to inspect what I think is a failing valve. Sure enough they concluded that the valve is failing, but they did their typical sales thing and offered to: replace the valve with modern technology and keep the resin tank in place, re-resin the tank, and flush the brine tank. What is the life of resin? The Culligan guy said "15-20 years maximum". The system has now been unplugged for 3 weeks while we consider these options - does it take much to just start this back up if I go buy my own valve and install it?
If your water softener has been out of service for some time or is old, it would be appropriate to sanitize the unit - see SOFTENER CLEANING & SANITIZING for that procedure.
The life of water softener resins is indeed limited and I agree with your Cullligan representative. But you might want to take a look at
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