May 4, 2015

Saltwater pools have become one of the most common trends in the swimming pool industry over recent years. Naturally, many of our customers have questions regarding salt sanitation. We hope the following information will be helpful in determining whether or not salt is the right fit for your own backyard or commercial project.

What is a saltwater pool?

Rather than using a traditional (usually off-line) sanitizer such as liquid chlorine, or chlorine or bromine tabs, a saltwater pool uses a chlorine generator to produce chlorine on site, from regular table salt (NaCl) which is dissolved in the pool itself.

During circulation, saltwater passes through an electrolytic cell that uses electric charges to separate the sodium and chlorine molecules. The chlorine (Cl-2) then reacts with water to produce hydrochloric acid (HCl) and hypochlorous acid (HClO) – a highly effective disinfectant. During sanitation reactions with bacteria and other microorganisms, chlorine ions separate to form chlorine gas and bond with sodium once again, priming the system to begin the process all over again.

Now, let’s explore some of the pros and cons of this type of system.

Pros of saltwater pools

  • The feel of the water on the skin
    • This is probably the most discussed advantage of salt water pool. The feel on the skin is “smoother,” more like ocean water.
  • Better water quality and less eye irritation
    • Because the unit is chlorinating continuously when the pump is in operation, the sanitizer level is more consistent. Properly maintained disinfection can be gentler on the eyes.
  • No need to purchase, handle, or store chlorine
    • Other than rare situations in which the chlorine generator is not working properly or keeping up with chlorine production due to extremely high water temperature, heavy swimmer load, rain, etc., there is usually no need to purchase, handle, or store traditional chlorine.

Cons of saltwater pools

  • Initial cost and over-hyped savings
    • Chlorine generators are often sold as a cost-savings system, but that is not necessarily the case. The installed price for a high quality residential chlorine generator is typically $1,500-$2,000. Depending on the extent of your use, that covers the cost of chlorine for 5-8 years, which is about on par with the average lifespan of a chlorine generating unit before replacement is required. Over the life of your pool, the overall costs are generally comparable.
  • A saltwater pool is not actually “chlorine-free”
    • This is less of a con than a misconception. A “salt water pool” is still a chlorine pool. The chlorine production in a saltwater pool is essentially sodium hypochlorite (liquid chlorine). If you are truly allergic to chlorine, a chlorine generator is not the system for you.
  • Salt is corrosive
    • Salt can be corrosive to coping (especially flagstone), stone waterfalls, decks, and any metal INCLUDING stainless steel (such as diving board bases, pool ladders and handrails, light niches, poolside furniture, stainless steel filters, etc.). Annual application of a penetrating sealer to coping and other stone materials, and fresh water rinsing of coping, deck, and metal, can be helpful.
  • Environmental concern/backwash restriction
    • Due to the salinity of the water and its potential harm to sensitive wildlife, many municipalities have restricted the backwashing or draining of saltwater pools into the storm sewer system.
  • Can cause scale forming deposits on the tile/spa spillways/waterfalls
    • Salt can cause scale deposits to form on tile/spa spillways/waterfalls. Frequent brushing areas and use of a scale inhibitor are recommended to prevent this scale buildup.
  • Does not work with cold water
    • Chlorine generators do not produce chlorine when the temperature reaches a certain level (approximately 55 degrees).  In the unlikely event the temperature drops to this level during swim season, chlorine (probably liquid) will be necessary in order to maintain disinfection.

Testing Still Required

Another misconception with chlorine generators and other types of “automation” is that they do not replace traditional water testing and maintenance. Even though sanitizer levels should be consistent in a salt water pool, water testing and cell cleaning/replacement are very important. Chlorine generators only produce chlorine; they do not maintain the water chemistry of the pool; as such, the pool water must still be tested and appropriately balanced at least 1-3 times per week.

Weigh the Pros and Cons

It is very important to weigh the pros and cons before deciding which sanitizer is best for your project. There are situations in which a chlorine generator will work exceptionally well, and others in which it may not be appropriate. We are happy to provide our input; as always, our ultimate goal is to deliver a product that demonstrates the performance and visual appeal that each and every customer desires and deserves.