The Complete Guide to Salt Water Hot Tubs

The Complete Guide to Salt Water Hot Tubs


What is a Salt Water System?

Salt water systems are found on many high end hot tubs and are widely regarded as the pinnacle of water care systems due to their ease of use and low maintenance. With just a little salt added to your spa’s water, the system will automatically generate chlorine when needed to keep your spa water clean and clear for up to a full year until you have to drain and refill.

Some of the benefits of Salt Water systems include: 

Salt Water System Maintenance

Maintenance varies between brands, but let’s use the ultra-popular FreshWater Salt System for our example. This system is found on high end Hot Spring models. Although the system regulates chlorine on its own, environmental factors mean the system needs adjustment around every 10 days. A handy control panel prompts you to dip a test strip in the tub and adjust the salt system accordingly.

Other than simple routine adjustment, the system runs off of disposable cartridges that last 4 months. So with three cartridges and routinely adjusting your system, you can avoid having to drain and refill your water for up to a year!

What About Other Water Care Systems?

Traditional Water Care

Traditional water care means the spa owner manually adds Chlorine or Bromine to the spa once a week and before each use. You should only purchase chemicals from an authorized hot tub dealer to make sure you get the highest quality products to assure your spa and water stay healthy. The amount of maintenance required by the spa owner depends on how frequently they use the hot tub. With regular hot tub use, the spa water should be checked with a test strip each time the hot tub is used.

Ozone Systems

Ozone with MPS and Silver Ions is slightly more expensive than traditional water care. It is still a fairly manual process, but requires a little less interaction from the spa owner than manually adding chlorine or bromine. Spa owners enjoy this system because it only requires a very small amount of chlorine and chemicals.
Ozone systems were once considered the best water care option for hot tubs, and has since become the industry standard for hot tub water care in most middle tier hot tubs. Ozone water care systems use powerful oxidizers – ozone and MPS – with silver ions to decrease the need for chlorine. Once the Ozone unit is installed, it continually releases tiny ozone bubbles into the spa water. The silver ion cartridge then automatically releases silver ions into the water that inhibit the growth of bacteria. The spa owner then has to manually add MPS to the spa with each use, and a small amount of chlorine once a week. The silver ion cartridge should be replaced every three months, and the ozone unit will need to be replaced every 4-5 years.

Salt Water FAQ

What testing has been done on the Salt Water System?

The salt system was developed, and lab tested for more than three (3) years while internal and field beta testing was completed over a two (2) year span. The results from the beta were very helpful in refining the installation and operation of the system and the feedback was very positive with users indicating that their spa water was much softer (less irritating) and the system was easy to use which resulted in them using their spa even more than with their previous water care system.

What is the difference between bottled chlorine and chlorine generated by the FreshWater Salt System?

Like bottled chlorine, the chlorine generated by the FreshWater Salt System is sodium hypochlorite. However, bottled (dry) chlorine contains stabilizers like cyanuric acid When stabilized chlorine is repeatedly added to spa water, the cyanuric acid can accumulate over time and cause irritation to the skin and eyes typically associated with traditional chlorine water care. With the FreshWater Salt System, there are no stabilizing acids added to the water so the water is softer and more enjoyable.

Does the Freshwater Salt System cause a chlorine smell?

The FreshWater Salt System cleans the water without creating chlorinated or brominated
byproducts. It is these byproducts that ultimately lead to the strong chlorine or bromine
smell often associated with traditional spa water care. So, it is less likely you will experience
any strong chlorine odor when using the FreshWater Salt System.

How do I test and balance the spa water?

FreshWater 5-Way Test Strips. They are specifically calibrated to measure the water for your salt system.

How much salt does the FreshWater Salt System use?

The amount of salt added to the water is based on the spa size (5-10 cups depending on spa
model). This is less than human tears and 10x less than sea water. Unlike pool systems that require high levels of salt (5,000 ppm), the FreshWater Salt System operates with a minimal amount of salt (1,500-2,000 ppm), which is non-corrosive when the water is balanced to the specified parameters.

Can I use Silver with the FreshWater Salt System?

Yes, silver is highly recommended to use in conjunction with the FreshWater Salt System to inhibit bacteria growth, minimize chlorine demand, and extend the life of the water. Since the salt system cartridge has its own housing in the bartop, the silver cartridge can be used per the instructions on the box, adapters are not needed.