SNS-salt water hot tub

What is a Salt Water Hot Tub

In 2010, Watking manufacturing introduced the ACE Salt Water System for their Hotspring and Caldera Hot Tub lines.  Saltwater sanitation systems have been around for a while and are nothing new.  What is unique and different is that salt water has been adapted for specific use in their hot tubs.

If you are unfamiliar with saltwater sanitation, it is the process of using sodium chloride (salt) and converting it into chlorine.

What Hot Tubs Have Salt Systems Abvailable

As of this article, only Watkins has Freshwater Salt available on specific models of hot tubs. There are other third-party manufacturers of salt systems on the market. 

I would use caution when considering  a third-party salt system. Some hot tub manufacturers may reject a warranty claim if the salt system chemistry damages the parts. If parts become corroded or damaged due to poor water balance, the salt system may have caused the problem, and the manufacturer will not cover any warranty claim.


Why would you want a saltwater hot tub?

  • Automatic Chlorination. It makes its own chlorine for a Year.

  • Fewer Water Changes. Good for the environment and your water bill.

  • Softer skin. Not as harsh as chlorine or bromine-treated hot tubs.

  • Helps your Joints.  Like Epson Salts, a saltwater hot tub helps your joints feel better and more flexible. 

  • Fewer Chemicals.

  • Less Irritation.

  • Fewer Odors.

How to Use the System

In the past, I have attended Watkins Wellness Freshwater Salt training sessions. The following is everything I learned and the best practices for their system. I also added some general overall water care tips. These instructions should apply to most saltwater systems as they work similarly. Of course, you do want to check the owner manual of any system you install.

Salt Water Hot Tub

Startup And Refilling


Before turning on the power, you first want to fill your hot tub by locating the filter compartment and removing the gray filter cap. The standpipe should be hollow. Place your hose down inside the standpipe and turn on the water. This step is essential to prevent air locks. If you get an airlock, you can read my post, I Just Got my Hot Tub, and I have Problems.”   You will see a video from my YouTube channel to help you solve this problem. 

The preferred method to fill your hot tub is the Hotspring freshwater pre-filter hose attachment. This will remove minerals and other containments from your water without adding any phosphates. 

Note: Only one filter standpipe will be hollow if you have multiple filters. Also, if you have a Mineral Stick, it is usually set inside the standpipe and should be done before replacing the filter cap. Mineral Sticks help kill bacteria, so your freshwater system does not have to work as hard when you have a lot of bathers in your hot tub.

If you have not checked or are doing a water change, ensure you have installed a freshwater salt cartridge, not the dummy plug that came with your hot tub. During this initial startup, the freshwater system should be set to Zero until the startup steps are completed. Reference the Hotsprings Freshwater Owners Manuel

Note: If your Water is high in minerals, use a Stain & Scale Product to remove them per the directions. Rinse your filters after usage. Be sure to check the label to see if it contains any phosphates. Some stain & scale products will add phosphates to your hot tub and may cause problems with your water chemistry. 

Do not add any other chemicals or make water adjustments for 24 hours. Some chemicals will react with your water’s minerals and can cause the water to change color. You will have to drain your tub and start over if this happens. 

After the tub is filled, run the jets to purge the line and move the diverters from side to side.

Now you can add the salt for your size hot tub per the manual. Ensure the water temperature is at least 95 degrees, as it dissolves faster in warm water. Start by adding half the recommended amount with your jets running. 

After five minutes, use the test strip to check the amount of dissolved salt. Continue with one cup at a time and test until you reach the proper reading. Your goal is 1750 ppm. The topside control test button checks for proper operation of the system.

Using a test strip, check your water balance to ensure your pH (7.2-7.8), Alkalinity (80-120). Use a separate Phosphates test kit to check that you are under (300 ppb) and adjust accordingly. If Your logo light is flashing, this is normal and will continue to flash until all steps are completed.

Note: High Phosphates will consume the chlorine produced by your freshwater system and, if left unchecked, can also cause a green tint to your water. My blog post has more about this subject and the other causes of Cloudy And Foamy Water.

Anytime chemicals are added, run your jets for ten minutes with the cover open. Most chemicals are best added in or near the filter compartment when the water is 65 degrees or more. Anytime you make a phosphate adjustment, set the system to zero and rinse the filter after treatment.

If your water hardness is above 75 ppm. Use the vanishing act calcium bag per the instructions on the box. Your goal is 50 ppm. Be sure to rinse the vanishing act bag per the directions. If you don’t use it, keep it for future use, as water calcium hardness can change over time as you use your hot tub. A high calcium level will shorten the life of your salt cartridge.

Next, Establish a chlorine level of 5 ppm with granular or liquid chlorine, wait for Five, then test. Add more if needed and test again until you reach 5 ppm.

You can use your hot tub at this time but keep in mind the chlorine level you are trying to establish will go down or back to zero. Thirty minutes after using your hot tub, check your chlorine level and adjust it back to 5 ppm.

Day Two

Set the output level to 10 using the topside controls. Reference the Hotsprings Freshwater Owners ManuelNote: level 10 is the same as using the boost function.

Test your Water Chemistry and make any needed adjustments. If your chlorine is less than 3 ppm, add more until you reach 5 ppm.  

Days Three and Four

Test Daily and Maintain 3ppm of chlorine. Lower the Output Level to the level listed in the Owners Manual.

Day Five Plus

Once spa water is holding a 3 ppm chlorine residual, stop adding additional chlorine, adjust the output level as required, and use the Boost function as needed.

Water chemistry levels can take up to 30 days to settle and be consistent. As time goes on, you will fall into a routine that works for your usage.

Weekly Maintenance

Test for Chlorine. Adjust your output using the topside control to adjust your chlorine if it is high or low. You should not have to use any other chlorine to make these adjustments.

Note: It is not recommended to overuse granular chlorine with your freshwater system as it can actually cause chlorine lock from cyanuric acid in dichlor.

Using test strips check your Water’s Alkalinity and pH. Adjust accordingly. 

Test your water hardness and phosphate levels. It is essential to keep these in check as they do interact with each other.

Your goal is to be in the ‘Ideal’ range. Once you get past the 30-day mark, you can test less often. Keep on an eye on the pH level. With salt systems, it tends to drift to the high side.

Use a Spa Oxidizing Shock Once to Three times a week  (to eliminate soaps/oils), depending on your usage. Soaps and oils will cause cloudy and foamy water. I recommend and use it myself. Natural Chemistry’s Spa Perfect is a more effective alternative to the oxidizing shock.

If you are experiencing excessive foam or the water looks cloudy,  check out my blog post, “My water is cloudy and foamy.”

Monthly Maintenance

Check your filters for debris and discoloration. If dirty, rinse them in your laundry sink with our garden hose.

Your vinyl spa cover does require maintenance for longer life. A cleaner/protector should be applied. Fabric Covers do not require any special care.

Check your water level and top it off if needed. Check your hot tub with a Salt test strip. You want to be sure you have enough salt. If your Logo Light is flashing, it may be asking you to check the system for proper operation. Check your manual for more information.

Every Four Months

Change the Salt Cartridge. Ensure you turn off your hot tub or use the suspend mode accessed through the topside control per the manual.

Thoroughly clean the filters using a Filter Cleaner product, per directions on the packaging. I prefer filter cleaners that are long soaks vs. quick rinse solutions. You should rinse thoroughly and let them air dry before putting them back into the hot tub.

Don’t forget to change the Mineral Cartridge if you are using one.

Yearly Maintenance

I recommend Natural Chemistry’s Spa Purge or similar products for cleaner and healthier plumbing by following the directions on the packaging.

Drain and refill the spa.

Quick Tips:

Use the boost control 24 hours before and after a heavy bather load. It takes time for your hot tub to recover from heavy use.

For the first 30 days, test often. The spa size + frequency of use + the number of bathers, + usage time all contribute to the overall water condition.

10-Day Timer notification

After ten days, you will get a flashing water care icon on the tub’s topside control panel if the spa has had no interaction or the output level has not been confirmed. The level automatically will drop to Level 3 after 15 days. At 20 Days output level drops to one.

10-Day timer reset

Any Output Level change or pressing “Confirm” will reset the timer, and the “Later” command will postpone for 3 hours.

I hope you found this helpful

Freshwater Salt Startup Video


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