Here at the Spa Shoppe we get a lot of questions about salt water sanitization systems. How do they work? Are they worth the expense? Do I need get new equipment that can handle saltwater? Are they really chemical free?

For this post I thought I would go over what makes salt water different from traditional sanitization systems, weigh out the pros and cons of salt water systems, and dispel some common misconceptions about them.

How Does Salt Water Sanitization Work?

In a salt water sanitization system regular table salt ( sodium chloride), dissolved in water, is passed through a low voltage electric current. This process is called electrolysis which energizes the salt molecule and then combines it with hydrogen found in the water to form usable chlorine sanitizers. As long as the system is running, and water is flowing past the cell, it will continue to produce these chlorine sanitizers. The rate at which it produces the chlorine is set by you, allowing you to turn it up or down as outside temperatures , and usage, change over the season. This same principle is also used in some hot tubs to produce bromine from sodium bromide.

Benefits of Salt Water Systems

The first benefit of switching to salt water is the improved water quality. This improvement is partly due to the salt itself, and also partly due to the fact that you’re not adding chlorine pucks. A “chlorine puck” is generally less than 50% actual chlorine, the balance being made up of stabilizers, binders, and other fillers. As these build up in the pool, they can give the water a harsher, more “chemical” feel to the water. By not needing to add any (or very few) chlorine pucks, you avoid that build-up, and are left with more natural feeling water. Salt water itself is also naturally “softer” feeling.

The other main benefit of switching to a salt water is the ease of maintenance. Since they produce their own steady supply of chlorine, you do not need to manually add chlorine in a salt water system, reducing the weekly upkeep, while also avoiding having to handle chlorine. On top of that, if you are away for several days or more you do not need to worry about your pool becoming cloudy or green due to lack of chlorine. With all of that said, you will still need to ensure the water is properly balanced, brush the walls of the pool, and shock it periodically, typically every 2-4 weeks, to prevent any problems from arising.

Drawbacks of Salt Water Systems

The main downside of a salt water system is the potential for corrosion. Salt water is more corrosive than fresh water, the more salt present in the water, the more potential for corrosion exists. To help combat this, many manufacturers have come out with low salt units. Hayward, for instance, have introduced the AquaRite Low Salt system which will effectively run at half the salt level that standard systems require.

Another drawback of salt systems is their tendency to slowly raise the pH of the water, which, if left untreated, can lead to scaling and water clarity issues. This pH climb can be easily combated by periodically adding a pH reducing chemical, usually once monthly.

Some Misconceptions About Salt Water Systems

  • Salt water systems are completely chlorine and bromine free. As we’ve already seen that is not the case; they simply produce their own supply of chlorine. They will typically also need to have some chlorine added at the beginning of the season, and after heavy uses to maintain a safe level of chlorine.
  • All you do is add salt and it takes care of everything else. Again we’ve seen that that is simply not the case. While it does eliminate the need to manually add chlorine; the water still needs to be balanced, shocked every few weeks, and salt needs to be periodically added as water splashes out and is replaced by freshwater.
  • Salt systems will save you a ton of money on chemicals in the long run. While it is true that you will save money by not having to buy nearly as much chlorine, those savings are negated by the initial costs of buying the system, and the cost of replacing the cell every 5-7 years. When looking over the span of 10 or more years, the overall cost difference between using traditional chlorine and salt water chlorination are minimal.

Proper Maintenance of a Salt System

So how do you properly maintain a salt water pool?

  • The salt cell will not efficiently generate chlorine until the pool water reaches a temperature of around 70 degrees Fahrenheit, so, for the first few weeks a salt pool is opened, you will need to manually add chlorine to prevent the pool from going cloudy or green. The amount of chlorine should be minimal since cold water doesn’t grow algae nearly as quickly as warm water. A couple of chlorine pucks and some shock should be all you need.
  • The cell should also be chemically cleaned at least once a season with a special salt cell cleaner. Calcium and other minerals can build up on the cell through the year, greatly reducing its efficiency. A layer of calcium buildup as thin as a piece of paper can reduce the cell’s ability to produce chlorine by up to 50%. Cleaning the cell once a year will ensure that your cell is always working at peak efficiency, and, since it will not have to work as hard to maintain a chlorine residual, extend its lifespan.
  • If you’re having problems establishing a chlorine residual, you could have an excessive amount of phosphates in the water. Phosphates are introduced to the pool when organic materials, like leaves, enter the water. As phosphates levels increase they can coat the salt cell, inhibiting its ability to produce chlorine. If you think you might be having this issue ask for a phosphate test next time you get your water tested. Based on that test, you will add a phosphate remover, like Natural Chemistry’s Phosfree.
  • Most salt water systems come equipped with a super-chlorinate or “boost” function. This is used periodically throughout the season, and after heavy uses, to break up chloramines (used up chlorine responsible for red eyes and the distinct “chlorine smell”) and ensure that the water stays clear. When activated, this function turns the cell up to 100% output to rapidly build up the chlorine level and super-chlorinate (shock) the pool. This works the cell harder than normal and can reduce its overall life, while also increasing the chlorine level beyond what most people find comfortable. To maximize the life of the cell, and keep the chlorine level down, use a chlorine-free oxidizer to shock the pool instead of this boost function.
  • As previously mentioned, the cell will typically need to be replaced every 5-7 years.
  • Lastly, salt systems can only do their jobs when there is flow past the cell. Make sure that your pool pump is operating at least 12-16 hours a day, during the day, to ensure that the cell has time to produce enough chlorine to keep you water clean and clear.

When all is said and done, salt water systems do work, and work well, but they are not the chemical free, no maintenance solution that some people hope for. There are pros and cons to getting one installed, but if you’re willing to educate yourself on how to properly operate and maintain the system, they can be a very convenient, and reliable, system.

If you have any more questions about salt water systems, or any other water care issue, call our certified water care specialists at 905-666-5333. Did you like this post? Like us on Facebook ( or follow us on Twitter ( @thespashoppe) to get notified when new blog entries are posted.

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