Water softeners come in several shapes and sizes from tall tanks to short tanks, one-piece units with the brine tank built-in, and even water softeners with two tanks. If most water softeners use a single tank, why do some water softeners have two tanks?
A water softener may have two tanks so that one tank is softening your water while the other tank is regenerating. Two tank water softeners are also used when a high volume of water is needed by having water flowing through both tanks at the same time.
There are several advantages to using a dual-tank water softener for both commercial and residential applications. Although a two-tank water softener can be more expensive than a standard single tank water softener, they do work well when you need the special advantages that they offer.
Dual-tank water softeners can deliver constant soft water or a higher volume of water flow.
Many people that see a water softener that has two tanks do not really understand the purpose of the two tanks, often feel that having two tanks is just to make sure that the water is totally soft when it comes out of the water softener.
It may appear that with a two-tank water softener, the water first goes through one tank, and then it goes through the other tank to make sure that your water is soft, but that is not how a two-tank water softener works at all.
In most applications, both tanks of a dual-tank water softener perform the same function. They both soften your water by the process of ion exchange as it flows through the water softener resin in their tanks.
The only function that will vary from one configuration to another is if your water is running through one tank at a time or through both tanks simultaneously.
A two-tank water softener can be used in one of two ways.
The most common way that a two-tank water softener is used is by alternating between one tank and the other for softening your water.
Your water flows through one of the tanks and softens your water as it goes through the water softener resin that is in the tank.
When the resin in the first tank needs to regenerate its water softener resin so it can remove more hardness from your water, the system switches over to the second tank to soften your water for uninterrupted softened water to your home.
Once the system has switched tanks, the water softener will regenerate the resin in the tank that was softening your water before so that it will be ready to soften your water again when the second tank is ready to regenerate its water softener resin.
The second most common application for a two-tank water softener is when both tanks are used to soften your water at the same time to allow for a higher volume of water through the system when high water usage is needed.
Small to medium-sized homes with moderate water usage may use an alternating two-tank water softener for the benefit of continuous soft water where a larger home may need the benefit of a higher water flow of a two-tank water softener to provide enough water to the entire home.
Is a dual-tank water softener the same as having two water softeners working in series?
A dual-tank water softener is a single water softening system that uses two tanks which is not the same as having two water softeners one after the other.
A dual-tank water softener functions with one control valve that controls the water flowing through the tanks and the regeneration of the water softener resin of each tank.
Having two water softeners in series is having two separate water softeners, each having its own control valve that only regenerates the water softener resin for one water softener system.
How does a dual-tank water softener deliver constant soft water?
Check out this quick video!
A two-tank water softener is able to deliver a constant supply of softened water because it alternates from one tank to the other before the present tank is unable to soften your water any further.
By shifting the water flowing through the water softener from one tank to the second tank with freshly regenerated water softener resin there is no interruption in soft water to your home.
Once the system has switched resin tanks, it will regenerate the first tank and repeat the process once the water softener resin in the second tank is ready to be regenerated.
Two tanks at once mean twice the water flow.
Commercial buildings or large homes requiring lots of available softened water will be able to use both tanks of a two-tank water softener to double the amount of water that could normally be delivered by a single tank water softener.
The disadvantage of using both tanks at once is that the tanks will normally be regenerated at the same time.
But since most water softeners can be programmed to regenerate when no water is needed for the home or building, this is usually not an issue for a business or even a home when most people in the home will be sleeping at night when a water softener is normally programmed to regenerate.
Do I need a dual-tank water softener for constant soft water?
If you want to have soft water 24/7, your water will need to always be going through a bed of water softener resin which means that a single tank water softener simply won’t do because at some point, it will need to regenerate its water softener resin and during the regeneration process, you will not have softened water.
Only by using a two-tank water softener can your water continuously run through water softener resin by switching from one tank to the other and then regenerating the resin in the first tank.
When is a dual-tank water softener needed for high water flow?
When there will be many people in a home or building using water at the same time, a single tank water softener may not allow enough water to travel through it.
Multiple showers, sinks, washing machines, kitchens are used at the same time will often need a two-tank water softener to keep up with the demand for soft water when many people need softened water at the same time.
Are dual-tank water softeners better than single tank water softeners?
There really is no difference in water softening ability between a single tank water softener or a two-tank water softener. Your water goes through a bed of water softener resin to remove hardness from your water in both systems.
Just because a two-tank water softener may cost more than a standard single tank water softener does not mean that it is better, it just is used for special circumstances.
How much do dual-tank water softeners cost?
Two tank water softeners often cost considerably more than a single tank water softener simply because there is a second tank with water softener resin in it and the control valve is a bit more complicated than a single tank water softener.
Depending on what brand of two tank water softener you choose, they usually start at about $2000.00 compared to a standard water softener of similar ability that may cost about half the price of the two-tank system.
Whether you choose a single tank water softener for basic water softening or you like the special advantages of a two-tank water softener, getting the correct type of water softener for your needs is what is important.
If you have a large family living in a large home where water usage is high, you may want to consider a two-tank water softener over a single tank system. But if you have an average-sized home with an average-sized family, a standard water softener may be the best choice for you.
Hi Paul, my grandson has a two resin tank system. The first one has a Watershield digital valve and the brine tank connects to this one. The second tank, similar in diameter, has a Watershield Gold controller but the brine tank does not connect to this one. How does this work exactly? How does the second tank regenerate with no brine? The second Gold valve also shows an Error 102. How can I fix that? Thanks.
Hello Rick and thank you for the question.
The second tank that is NOT connected to the brine tank is most likely NOT a water softener.
A second tank like you described might be used to neutralize the acid in the water, remove iron from the water, remove chlorine from municipal water, or remove odors from the water.
I would contact the water treatment company that installed your system for more details, but I believe that the second tank is NOT a water softener that requires brine.
I hope this was helpful!
Paul