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What is a Saltwater Hot Tub, the Ultimate Guide

11 Minute Read

Hot tubs are a popular choice for relaxation and hydrotherapy, but with so many options available, it can be overwhelming to choose the right one. One of the most common questions that arises when it comes to hot tubs is how to properly sanitize the water. While chlorine, bromine, ozone, and UV are all common methods, saltwater sanitizers have gained popularity in recent years. In this ultimate guide, we will explore what a saltwater hot tub is, how it differs from other hot tubs, and everything you need to know about this unique water care system.


What is a Saltwater Hot Tub

A saltwater hot tub is a type of hot tub that utilizes a salt-to-chlorine generating sanitation system. This system is available in various hot tub brands and models and offers a different approach to water care compared to traditional methods. Contrary to popular belief, saltwater hot tubs are not completely natural or even chlorine and chemical-free. Instead, they generate their own chlorine through a process called electrolysis.


During electrolysis, an electric current is passed through the saltwater causing a reaction that forms sodium hypochlorite, and hypochlorous acid is formed which reacts to produce chlorine. The amount of chlorine created is intended to keep the hot tub water clean and free of contaminants under normal usage. After filling the spa or during periods of heavier use, additional chlorine or other chemical sanitizers may be required to maintain safe sanitizer levels.


These systems are typically called an “open loop system” meaning the system does not change it’s level of output unless manually reset, it lacks automated adjustment in response to levels of chlorine detected. They are designed to run a set amount of time per day in order to generate the needed levels of chlorine. These systems can continue blind dosing excessive amounts of chlorine even if there are output levels set for the amount of chlorine desired. Alternatively, they can underproduce the required sanitizer levels and need to be supplemented with chemical sanitizers to reach safe levels. Owners should check their spa’s chlorine levels regularly to ensure they are safe.

 

Benefits of a Saltwater Hot Tub

  • Saltwater hot tubs offer several benefits that make them an attractive option for hot tub owners.
  • The unique feel of the water treated with a saltwater system. Many people enjoy the soft and smooth texture of saltwater, which can enhance the overall hot tub experience.
  •  Saltwater systems can provide a gentler form of water sanitization compared to using only chlorine or bromine sanitizers. Because the system continuously produces chlorine, it has less variability in chlorine levels and subsequently tends to have lower peak levels of chlorine.
  • Reduced “Chlorine” smell” – Though a properly maintained spa should never have that familiar smell we associate with public pools, saltwater spas largely eliminate the chance of having that “chlorine smell” in your spa.
  • Less frequent addition of sanitizing chemicals compared to traditional methods. While regular maintenance is still necessary, the frequency of adding sanitizing chemicals can be significantly reduced with a saltwater system, making it a convenient choice for those looking for a lower-maintenance hot tub experience.
  • Reduced frequency that the spa water needs to be replaced, down to 1-2 times a year from the more standard 4 per year interval.
  •  There have been claims of increased buoyancy due to the presence of salt in the water. There may not be a material improvement in buoyancy as the levels of salt present are about 5% of the level of salt in ocean water.


Drawbacks to Saltwater Hot Tubs

  • Costs – Saltwater sanitation for hot tubs can easily cost more than other approaches to sanitation. Salt is inexpensive but the cells used to create chlorine from the salt water are not. Total cost of ownership can often be higher with a salt system. See the maintenance and care section below for detail on costs and replacement intervals.
  • Will need to monitor and maintain salt levels
  • While reducing the need to add sanitizer, these systems require you to test for salt levels and add as needed to maintain the required amount of salt in the water.
  • Cleaning the salt cell electrodes – in order to keep chlorine production at optimal levels, the electrodes will need to be removed and cleaned about 4 times a year in a standard salt setup or, with the FreshWater® Salt System from HotSpring®, they will need to be replaced with a new cartridge 3-4 times a year.
  •  Minimal reduction in maintenance – you’ll still need to test your water regularly, change filters at the same intervals, and use the same chemicals, with the exception of sanitizer. Reduced frequency of adding sanitizer and changing water is offset by increasing the need to balance salt levels and clean and replace the chlorine-generating electrodes at regular intervals.
  • Saltwater damage - Increased risk of damage to certain parts, like rubber seals or metal fixtures, from continual exposure to salt water. If you have little ones that like to splash, afterwards you may want to hose off the surrounding area to avoid damage to plants or other things that are sensitive to water.
  • Inflexible - Best use case requires predictable usage level at steady intervals. If you have a variety of the number of people using the spa or cluster your use around weekends, this can overload the steady levels produced by salt systems.
  • Chlorine will likely still need to be added – looking at the manual from one of the most popular salt systems, it indicates clearly that it is not an automatic water care system. It is designed for a typical user. Frequent use can require you to supplement sanitizer generation with Chlorine.
salt water hot tub

Maintenance and Care

 While saltwater hot tubs offer benefits, they still require regular maintenance and care. It is important to monitor the chemical makeup of the water to ensure it is safe for use.


Maintaining proper pH and alkalinity levels is crucial for the saltwater system to work effectively and achieve safe levels of chlorine in the water. If the pH and alkalinity are not within the recommended range, the system may not function properly, and safe levels of sanitation will not be achieved.


Maintenance for saltwater spas can include:

  • Test and balance the water 2–3 times per week. If you use the hot tub often, test the sanitizer levels more frequently.
  • No change from other spas with respect to testing and balancing pH, Alkalinity, Calcium.
  • Clean the hot tub filter every 2–4 weeks.
  • Remove and clean the salt cell every 60–90 days (the cell is replace every 3-4 months with the FreshWater® Salt System, for about $100 per cartridge or $300-$400 per year)
  • Replace the salt cell every 3-5 years for non-cartridge cell systems (cost is around $500-$700).
  • Test and adjust the salt system around every 10 days. You can use a test strip to adjust the salt system. Use of pool-grade or spa-grade salt is recommended
  • If you have hard water – it is recommended to use a water softener to reduce calcium levels when you fill the spa, but make sure the minimum calcium levels are still there by topping off with untreated water.
  • Additionally, occasional shock treatments and the addition of stabilizer may be necessary to maintain water clarity and balance.
  • Drain and refill the spa with new water at least annually - more frequently with heavy use and supplementation of chlorine generation system with chemical sanitizers.
  •  Modify your chlorine output levels if you are planning to increase or decrease usage levels (parties, away on vacation).

Saltwater hot tubs require similar maintenance to traditional hot tubs. To better understand the maintenance required for a system, request an owner’s manual for the system you are interested in to see what care is required to use and maintain that system.

 

Cost Considerations

When deciding whether to invest in a saltwater hot tub, cost is an important factor to consider. The initial cost of purchasing and installing a saltwater system may be higher compared to traditional hot tubs with chlorine or bromine sanitizers. Additionally, the ongoing cost of maintaining a saltwater system, including the replacement of the salt-chlorine generator and cartridges, should be taken into account. The cost of using chlorine may be around $100 per year while replacing just 3 cartridges in the FreshWater® Salt System will cost about $300 in a year. The cost of salt should be well under $50 per year, even using the recommended pool grade salt.

 

Outside of the difference in sanitizer use, a saltwater spa will require much the same maintenance routine and chemicals to keep the water balanced and clear so the primary cost differential is focused around the need to purchase sanitizer vs a system to generate it.


However, it is important to weigh these costs against the potential benefits and convenience of a saltwater system. The reduced frequency of adding chemicals and the unique feel of the water may be worth the investment for some hot tub owners. Ultimately, it is a personal decision based on individual preferences and budget considerations.

 

Alternative Water Care Systems

While saltwater hot tubs have their advantages, there are also alternative water care systems worth exploring like ozone and UV light systems. One such system combines proven UV-C technology with ozone.


The Jacuzzi® CLEARRAY Active Oxygen® system exposes the hot tub’s ozonated water to a UV-C bulb that energizes the molecules and unlocks Active Oxygen to clean. This system works in tandem with multiple stages of filtration and enhanced circulation to continuously keep the water clean for a longer duration.


There are also systems that use minerals and enzymes to keep water safe, as well as ones that dispense steady levels of sanitizer, like the FrogEase™ system. This system can mimic the slow steady release of chlorine produced by a salt system, but with a simple floating dispenser that reduces the need to add sanitizing chemicals for weeks at a time. 

saltwater hot tubs

Choosing the Right Water Care System

To determine the best water care system for your hot tub, it is recommended to visit a local hot tub showroom. Knowledgeable hot tub dealers can provide information on various water care systems available in different hot tub brands and models, helping you make an informed decision based on your specific needs and preferences.

When considering a saltwater hot tub, it is essential to understand the maintenance requirements, potential costs, and benefits associated with this type of system. By weighing these factors against other water care options, you can make an educated choice that aligns with your budget and desired hot tub experience.

 

Conclusion

In conclusion, a saltwater hot tub is a hot tub that uses a salt-to-chlorine generating sanitation system. It offers a unique feel and a gentler form of water sanitization compared to traditional methods. However, it does require similar levels of regular maintenance and the higher costs should be considered.

If you expect to use your spa at steady intervals with time in between sessions, or without much variation in the number of users, you may find that saltwater sanitation systems are a great fit. Additionally, if you have highly sensitive skin and have tried and really liked the feel of the water on a salt system, then this could be the choice for you.

When choosing a water care system for your hot tub, it is important to evaluate the pros and cons of different options and consider your individual preferences and budget. Whether you opt for a saltwater system, UV and ozone, or other water care methods, the goal is to create a clean and enjoyable hot tub experience. Visit a local hot tub showroom to explore the various options available and find the best fit for your needs.

 

Disclaimer - In this article, we’ve used brand names not affiliated with Jacuzzi Group. All information, including pricing and product details, was accurate at the time of writing and may change without notice.


The following registered trademarks are owned by companies not affiliated in any way with Jacuzzi Group. Hot Spring®, FreshWater®, are trademarks owned by Watkins Manufacturing Corporation. Affiliations: Jacuzzi® is a registered trademark of Jacuzzi Group. All rights reserved.

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ashley fields

About The Author: Ashley Field

Director of Training, Jacuzzi Group

Ashley Field has been with Jacuzzi Group since 2016, previously having worked for Discover Financial Services and Taco Bell. When she was initially contacted about an opportunity with Jacuzzi Group, she loved the idea of building... Read Full Bio