Salt Water For Hot Tub Sanitizing? Things to Know Before You Decide

The Rest Of the Story

Here’s the rest of the story about using salt water systems for sanitizing your hot tub. Salt water systems are being promoted as the better way to keep hot tub water clean because allegedly:

1. They require less work because it’s automated and “hands free”.

2. They don’t depend on harsh chemicals like chlorine, bromine or spa shock

3. They use an inexpensive salt like table salt instead of 
expensive hot tub chemicals

4. They leave your skin feeling better because they don’t have harsh, traditional sanitizers

5. They are environmentally friendly because they use less chemicals

6. They use diamonds in the system to create powerful cleaners

Now, don’t get me wrong. Salt water hot tub sanitization can be beneficial if you are willing to understand the reality of the system. So, lets peel back the “hype” and look at the reality by examining each of the above claims.

Claim 1, less work: They require less work because it’s automated and hands free. The simplest answer to this claim is to look at one major hot tub manufacturer’s salt water sanitization manual.
The manual has 16 pages and includes 167 separate warnings, procedures and descriptions. This means that there is a huge amount of work required to operate and maintain this system. That manual is also full of dozens of required actions, making it much less “hands free” than traditional sanitizing. This includes fun things to do in maintaining a salt water system like removing the “cell” and cleaning it in an acid solution every three months, then reinstalling it.

Claim 2, no harsh chemicals: They don’t depend on harsh chemicals like chlorine. Well, they use salt and water to constantly produce five harsh chemicals in your hot tub water as you use the tub. Their main “powerful cleaner” is in fact good old chlorine. Salt water system manufacturers also recommend that you use normal spa chlorine and spa water shock any time that the tested chlorine level gets low…which can be frequently. So much for not using “harsh chemicals”.

Claim 3, inexpensive to use: It’s true that special hot tub salt is a little less expensive than hot tub chlorine ($7 a month for hot tub salt vs. $15 a month for hot tub chlorine). But, the salt is a very small factor in the overall salt water system cost. Here are the real costs:

1. Stand alone salt water systems: $500 to $700 to purchase and only a one year warranty.

2. Built in salt water systems: Up to $1500 and only a one year warranty. Sometimes the salt system is thrown in for “free” with the purchase price of the hot tub. Nothing is “free”. Wouldn’t you prefer a $1500 cash discount instead?

3. Cells have a 1.6 year average life and cost from $300 to $500 each time one is replaced.

4. Salt water system users also have to purchase:
• Hot tub chlorine
• Hot tub shock
• Special calcium remover
• PH up and PH down
• Stain and scale defense
• De-foamer
• 5 way test strips

So, over five to ten years, the salt water system users will save a little on the salt, but overall they will spend thousands of dollars more on water sanitization than traditional hot tub chlorine or bromine users.

Claim 4, skin feels better: It’s true that a little salt in the water will not affect your skin. However, the salt water system uses a special “cell” to generate elemental oxygen, chlorine and several other “powerful” cleaners and oxidizers. Your skin reacts to these powerful cleaners and oxidizers just like it will react to hot tub chlorine. Whether its salt water generated oxidizers or hot tub chlorine, having too much of either will not be beneficial to your skin.

Claim 5, they’re environmentally beneficial because of less chemicals: It’s true that when the 167 cautions and procedures for salt water sanitization are regularly and carefully followed, less harsh chemicals will be used . Similarly, if the simple procedures for using regular hot tub sanitizers are followed, much less harsh chemicals will be used. Oh by the way, the salt water system constantly uses electricity and requires the manufacturing of non environmentally friendly components that have to be thrown out on a regular basis.

Claim 6, diamonds are used in the “cell”: Not really. Just a diamond vapor is deposited in the “cell”. And, after the “cells” fail, they’re thrown in the trash. Not much diamond value after all.  Apparently, diamonds are referred to as a way to make the salt water systems appear more valuable.

The bottom line: Sadly salt water sanitization systems for hot tubs are over ”hyped”, making consumers confused. They are in fact, complicated to operate properly, expensive to purchase and maintain, create harsh oxidizers and have no special environmental advantages.


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14 Responses to “Salt Water For Hot Tub Sanitizing? Things to Know Before You Decide”

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  1. Rich s says:

    I fell like I was ripped off when I bought the ace salt system for my envoy hot tub . I was never told that the salt generator only last about a year an a half. The replacement cost will be over 900. Dollars it’s been over a year now and every time I look at my spa putting chlorine into my tub it just burns me.

  2. Gary Mumma says:

    Thanks for the tips on salt water hot tubs. You have helped me to decide if I want to change to salt water or not.
    The answer is a definite ▲”NO”

  3. Kathy Shaw says:

    My secretary at work said she had to quit using her hot tub because of her asthma. She went to a friend’s who suggested they get in the hot tub. She declined, but they told her it was salt treated, so she got in. She said she had not problems with her asthma. She knows I’m just starting to look at tubs, and that I have asthma. Any truth to this?

    • Fireside says:

      “Salt water” hot tubs simply use a complex process to generate and maintain a chlorine sanitizer from the salt which is part chlorine and part sodium. The needed active chlorine sanitizer is the same, regardless of its source. Many hot tubs already use a chlorine compound additive as the chlorine source.
      There is no known cure for asthma that comes from dilute chlorine/water immersion. If there were, it would be well known by now. We’re not medical experts, however 30 minutes of breathing the warm vapors from any hot tub could have temporary effects on the throat and lungs.

  4. Chris BC says:

    OK, I’m with you on the diamond hype. But, tell me how a salt water spa is going to be vastly different from my salt water pool. In 2 years in my salt water pool:

    1. No added chlorine
    2. No shocking ever, other than letting the salt cell run continuously for 8 to 10 hours if the chlorine level gets low.
    3. No calcium remover, ever. And of course if you use soft water you shouldn’t need to remove calcium. I used some soft water to fill my pool because it does need some calcium for the pebble tech surface.
    4. Only pH down, mostly via adding liquid acid which is not that expensive and is only needed once a month or so during swim season.
    5. No “stain defense” or “scale defense”. Again soft water or partial soft water will avoid scale buildup.
    6. No de-foamer. I could see where this would be very different in a hot tub with the jets running.
    7. Test strips are cheap and are a good idea for all pools and spas.
    8. I’ve only needed algaecide one time after a dust storm turned the pool brown and muddy. (Life in the desert problems.)
    9. Cleaning the salt cell with the same acid I pour in the pool (Muriatic acid) is very simple and easy.

    Otherwise the chlorine odor is almost nil, which can’t be said of standard pools, and the water is always clear unless stuff has blown into it. If I can get this in a hot tub why not?

    Clearly the salt cell dying every 12 to 18 months would be a huge negative, but aren’t there other alternatives? My Hayward salt cell for my pool is at least 3 years old and maybe more.


    • Fireside says:

      Our statements are based on the words taken directly from the hot tub industry’s largest “salt water” hot tub maker’s manual for their “salt water” hot tubs.
      Additionally, swimming pool water chemistry is totally different than hot tub water chemistry. The reason for the difference is two fold. 1. Hot tubs operate at 102F and not 70F. That temperature difference creates dramatically different chemical needs. 2. Hot tubs have about 300 gallons of water and pools have 10,000 to 30,000 gallons of water. This massive volume difference also creates totally different chemical needs.

  5. Cory AZ says:

    The opinions provided by the author does not match my real experience. Salt systems are not complex, but since they only produce chlorine (sanitizer), you may still have to maintain your spa with other products as needed. What a salt system does is help you maintain a proper chemical balance at all times so you don’t have to continually add other chemicals as you struggle to achieve a proper water balance. I have found that, overall, less chemicals are needed and that I need to use shock less often. The downside is cost. Salt cells are relatively expensive and do need to be replaced. A good quality cell will last 3+ years. Personally, I think the salt systems are worth the money for the easy maintenance they provide.

    • SpaSyl says:

      What brand of salt cell would you consider “good quality”? I am in the market to purchase a spa and want to use fewer chemicals

    • Fireside says:

      Thanks for your comments Cory.
      Here are the reasons that hot tub salt water sanitization systems are much more complicated for most people to use than traditional sanitization systems. This is taken from the salt water sanitization manual that comes with the industry’s largest hot tub manufacturer and salt water sanitization system provider:
      1. The manual has 16 pages and includes 167 separate warnings, procedures and descriptions. This means that there is a huge amount of work required to operate and maintain this system.
      2. That manual is also full of dozens of required actions, making it much less “hands free” than traditional sanitizing.
      3. Then there are required “fun things” to do in maintaining a salt water system like removing the “cell” and cleaning it in an acid solution every three months, then reinstalling it.
      Certainly a consumer can ignore all the above and do little to operate their salt water system in accordance with the manufacturer. The likely result is poor sanitizing and regular replacement of the 1 year warranty, $800 salt cell that makes the system work.

      The more traditional sanitizing systems are much simpler to use properly and less expensive to maintain.

  6. Pdoumas says:

    I think Cory’s arguments are excellent. I would be very interested to have a side-by-side similar comparison of a manual from a traditional spa, to compare to your so-called overly complicated manual accompanying a saltwater Spa. At this point, I feel like you have not backed up your argument with any facts, or sources. And, by sources I don’t mean vague references to in some unknown manual. Link? The manual for my car has 300 pages, but I feel like it’s maintenance is pretty easy. Just the number of pages or pictures of a manual is not evidence enough to support any argument against one type of thing or another. Please elaborate, oar lose any shred of credibility you have left.

  7. Pdoumas says:

    At $320 it is a bit expensive, but this unit has titanium plates, which are cleanable. No replacing cartridges year after year. Pretty affordable, considering some of the benefits that the salt water provides. My skin always feels better after a saltwater soak… There were some other cheaper systems to, but this one seemed like probably the best deal for aftermarket fitment to existing spa…. Happy soaking!

  8. Coffebrk says:

    This is a confusion article with which I disagree based on my personal experience. I have had a Jacuzzi Spa for the last 10 years setup with fresh water and a chlorine/bromine sanitizer. About 1 1/2 years ago I converted it to salt water and couldn’t be happier. Here is my experience:

    1.Yes , salt is less work. No chemicals other than the initial salt charge and PH down to adjust maybe every 3 months. The chlorine level with my Solazz generator has remained steady within a range on .08 to 1.2. We use the spa approximately every other day sometimes more on a weekend. I have added 1 cup of salt 2 months ago to bring the level up to 3500 ppm from 2800 ppm. The water is still crystal clear and I am seriously thinking of keeping it for another summer. There is no odor at all.
    2. The original manual that came from Jacuzzi when new had 28 pages with most of them being Gov required disclaimers and safety instructions. Yes we all know water and electricity don’t mix and can kill. That was for a fresh water setup.
    3. Yes skin does feel smoother and silky after a salt session. This is not only my opinion but everyone else that uses my spa.
    4. The Chlorine generator cost me $210 and is going strong still after 1 1/2 years. If it breaks I will get a new one for about $169 from Amazon and be ahead of the game. The instructions say that the polarity reverses automatically to purge the generator plate so cleaning is not required. When using fresh water, chemicals cost me about $300 a year.
    5. I don’t buy the totally different chemical needs for a pool versus a spa. They both require sanitized water to prevent problems for humans. The spa needs a slightly higher level of sanitation due to the higher temperatures of the water and ability of pathogens to propagate faster at higher temperatures. The salt water itself prevents many of the typical fresh water pathogens from existing.

    Bottom line for me and my family: We have used both fresh and salt water in the spa and and salt works best for us. Less work, lower cost, and better skin.

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