Since you are chemically altering the composition of your water through the process of softening it, the anode rod that you use has to match this new composition in a way that maintains adequate tank protection.
The truth is that water softener doesn’t go easy on our anode rods, and, therefore, we need to make sure that we get one that will perform well in this type of water. Keep scrolling to find out which anode rods are best for softened water and why!
The best sacrificial anode rods to use for softened water is the magnesium rod, as magnesium can keep up with high volumes of corrosives that are present in softened water. Another excellent option is a powered anode rod, since it can adapt to any type of water and will not deteriorate over time.
Can a Water Softener Replace an Anode Rod?
Even though anode rods and water softeners are both designed to protect you water heater tank from the contents of the water it holds, they do so in different ways and having one does not preclude the necessity of the other.
Softening your water can eliminate the risk of hard water minerals building up and compromising the metal of your water heater, but in so doing, it adds sodium to the water.
In fact, softened water contains quite a high concentration of sodium. Unfortunately, this element is an electrolyte and can accelerate the corrosion process.
So, far from not being able to replace the anode rod, a water softener actually increases the need for one.
Effects of Water Softener on Anode Rods
As mentioned, sodium is a corrosive substance, much like hard water’s minerals are.
Besides introducing a substantial amount of sodium to your water, water softening also leads to the lowering of water pH, and the elimination of problematic minerals in hard water.
As far as the effect of softened water on an anode rod goes, the sharp increase in sodium affects the lifespan of the anode rod since it causes it to corrode at a much faster rate. If the rod is not replaced in time, the water heater will begin to rust as well.
Typically, sacrificial anode rods can last about five years. In softened water, however, anode rods last only two to three years.
If your water is over-softened, your anode rod may only last six months.
In addition to this issue of corroding too quickly, you can have the opposite problem: the rod does not corrode fast enough. How does this make sense?
Well, typically, a relatively reactive metal is a good option for anode rods. This is because they are able to cope with the number of corrosive elements in the water, keeping them away from the tank, but they are not so reactive that they “overprotect” the tank, corroding needlessly fast.
In comparison, the vast quantity of corrosive elements in softened water requires a very reactive anode rod that will be able to keep up and not corrode slow enough that some of these elements are still able to attack the tank.
Performance of Sacrificial Rods in Softened Water
Sacrificial anode rods are made up of a material that is more reactive than the material of the water tank. This high reactivity attracts corrosive elements to the anode rod. As a result, the anode rod is corroded instead of the metal of your water heater tank.
All sacrificial anode rods serve this one purpose. But since they can consist of a variety of different materials, some materials may work better for softened water than others.
Aluminum Anode Rods
Aluminum anode rods are better for hard water that has a higher pH and higher mineral contents.
This is because aluminum is less reactive than other anode rod types.
Because of their lower reactivity, they can find a balance between preferentially corroding and lasting longer.
A magnesium rod would quickly be corroded in hard water.
Aluminum rods are also ideal for naturally soft water that lacks lots of minerals and corrosive elements.
Zinc Anode Rods
Thanks to their special properties, zinc anode rods are best-suited for odorous water.
Odor in water commonly forms due to the presence of sulfate-reducing bacteria in your water. While the bacteria are basically harmless, they produce hydrogen sulfide gas, which has a rotten egg-like odor that can be very bothersome.
An anode rod containing zinc can produce zinc ions as it corrodes. These ions can quickly kill these bacteria and eliminate the odor.
However, since zinc anode rods are typically zinc-aluminum alloys, they are not the best option for softened water.
Magnesium Anode Rods
Although they perform the same function, magnesium and aluminum rods differ in various ways.
For example, magnesium is far more reactive than aluminum.
Because of this, magnesium anode rods are best for softened water that has a lower pH and large amounts of corrosive elements.
The magnesium anode rod is reactive enough to keep up with high volumes of corrosives and thus can better protect water heater tanks from softened water.
Are Powered Anodes Suitable for Softened Water?
Unlike sacrificial anode rods, whose ability to protect your water heater depends on the type of water and the type of metal the rod is made of, powered anode rods are suitable for all kinds of water.
They are able to adapt to whatever water type they are submerged in by adjusting their voltage to the resistance of the water.
The current they produce provides protection against corrosives, even the high amounts of corrosives in softened water.
Magnesium vs Powered Anode Rod: Which Is Better?
Their Performance in Softened Water
While magnesium anode rods are suited for this environment because of their high reactivity, powered anode rods can perform equally well in any environment.
Either one can protect your water heater from corrosives in softened water.
While their performance is fairly evenly-matched, either one may come out on top when you factor in their additional benefits.
For magnesium anode rods, their benefit comes from adding magnesium ions to your water supply as the magnesium anode rod corrodes. Adding magnesium to your diet can improve your overall digestive health.
For powered anode rods, their main additional benefit comes from the elimination of bad egg smells in your water. Not only can the current protect your water heater tank from corrosion, but it can also kill sulfate-reducing bacteria in your water.
Comparing Lifespan
The main difference between a powered anode rod and a magnesium anode rod is how long they last.
While a magnesium anode rod is made to corrode over time, a powered anode rod will not deteriorate. Like all devices, though, a powered anode rod will malfunction at some point.
However, a magnesium anode rod in soft water may last only three to five years, while a powered anode rod can last from six to twenty years.
Price
Because powered anode rods last longer, use more complex technology, and are suited for all types of water, their prices are much higher than the prices of magnesium anode rods.
You can get a magnesium anode rod for $15-$60. A powered anode rod, on the other hand, will cost you anywhere from $100 to $250.
Maintenance
If a sacrificial anode rod fully corrodes, the corrosives in the water heater tank will immediately begin to corrode the metal of the tank.
Therefore, the maintenance of a magnesium anode rod includes yearly checks as well as replacing the rod every three to five years to prevent corrosion of your water heater tank.
The anode rod replacement cost depends on the state of the anode rod as well as who does it. The cost for professional replacement is often $200-$300.
Unlike magnesium anode rods, powered anode rods do not require much maintenance. They do utilize electricity, however, the cost of running a powered anode rod can be as low as about $1.36 a year.
Table Summary
| Magnesium anode rods | Powered anode rods | |
| Price | $15-$60 | $100-$250 |
| Protection from corrosion | Great in soft water. | Great in all types of water. |
| Lifespan | 3-5 years. | 6-20 years. |
| Need power outlet | No. | Yes. |
| Operational cost | Depending on how often it needs to be replaced. | About $1.36 per year. |
| Need to be replaced | Yes, more often. | Possibly, much less often. |
| Additional benefits | Magnesium is beneficial to digestive health. | Powered anode rods can eliminate bad egg smells. |
Which Anode Rod Should You Get for Softened Water?
While both options are good, magnesium anode rods are a better fit for those who are looking for a lower purchasing price and are willing to do the required maintenance and replace the rod more often.
Those who know their way around water heaters would save money installing and replacing this anode rod and would most likely have no problem with the maintenance required.
I recommend the Blue Lightning Magnesium Flexible Anode Rod (amazon link) for its flexibility and high ratings.
Powered anode rods are best for those who are looking for a longer lifespan and would prefer not to check and replace their anode rod.
It would also be ideal for those who struggle with bad egg smells in their water but would like an anode rod that lasts longer than a zinc anode rod would. However, it is not ideal for areas with frequent power outages or power surges.
I recommend the Corro-Protec™ Powered Anode Rod (amazon link) for its high ratings and the large range of compatibility. I also recommend you check out my ultimate powered anode rod guide to find out everything you need to know about these devices.
Sources
https://candjwater.com/2021/01/15/can-a-water-softener-save-your-water-heater/