Many hot tub owners in Canada are looking for ways of reducing their hot tub’s chemical usage. To help satisfy this need, hot tub manufacturers now offer a wide variety of different sanitization systems that are designed to reduce the amount of chlorine or bromine needed to keep hot tub water clean and clear. Today, we will review the most popular of these systems to help you understand their unique strengths and weaknesses.

What Do Hot Tub Sanitization Systems Actually Do?

Before we get into the various systems that are available for use in hot tubs, let’s first discuss what these systems are designed to do, and what they’re not designed to do.

Hot tub sanitization systems are meant to kill bacteria so that the chlorine or bromine residual in the water can do its job of keeping the water safe more efficiently. They are meant to be a way of reducing the amount of chlorine or bromine that your hot tub water requires, but are not meant to be a direct replacement for them. No matter what system you choose, you will still need to ensure that your hot tub water maintains a small residual of bromine or chlorine at all times.

Hot tub sanitization systems will also not help maintain water balance. To keep the water clear and comfortable to use, you will still need to regularly test and balance the water with balancing chemicals.

Why Do You Need Chlorine Or Bromine In Your Hot Tub?

Chlorine / bromine serve two functions in a hot tub.

  • In lower doses, they sanitize the water. Sanitization is the process of killing bacteria and other living organisms that are present in the hot tub.
  • In higher doses, they oxidize (“shock”) the water. Oxidization is the process of breaking down organic matter to prevent odour and cloudiness in the water. It will also convert spent chlorine and bromine back into effective sanitizers.

Why Do People Want To Reduce The Amount Of Bromine / Chlorine In Their Hot Tub?

Generally speaking, there are two reasons why someone might want to reduce the amount of sanitizer that they add to their hot tub.

They want a “softer” feel to the water. Hot tubs often get the reputation of having “harsh” water that drys out your skin and burns your eyes. The reality is that more often than not, these issues are caused by the balance of the water, rather than the chemicals themselves. That said, both chlorine and bromine can feel harsh on your skin in higher quantities and reducing the amount of chemical sanitizer that you add to the water will make for a more “natural” feel to the water.

They want to reduce their chemical costs. Some people simply don’t like the expense of hot tub chemicals. With the right chemical regiment and the right sanitation system, however, your hot tub chemical costs can be quite low. In fact, most of our customers only spend around $50 per month on their chemicals.

What Sanitization Systems Are Available For Hot Tubs?


UV sanitization systems use ultraviolet light to sterilize bacteria and other microorganisms in hot tub water. A UV-C “sterilization chamber” is added to the plumbing of the hot tub so that as the water passes through the filtration system it is exposed to germicidal UV-C radiation. This chamber also prevents the UV radiation from entering the hot tub and causing potential harm to its occupants.

UV light is an effective sanitizer but doesn’t oxidize the water. It will also only sanitize the water as it passes through the filtration system and doesn’t leave a residual in the water. UV systems therefore require the filtration system to be running in order to be effective.


Ozone sanitization systems inject ozone gas, a powerful oxidizer, into the hot tub water. As with UV systems, ozone based systems are installed in the plumbing of the hot tub and are active only when the hot tub filtration system is running. Unlike UV systems, the ozone is incorporated into the water. This means that the ozone will remain active in the water even when the filtration system isn’t running.

Ozone is a very effective oxidizer but does not sanitize was as effectively as UV will. UV systems can slightly alter water balance but as long as you regularly test and balance your water this shouldn’t cause any real issues.

Salt Water

Salt water sanitization systems are designed to convert salt into sodium chloride; an effective sanitizer. It does this by passing the water through a salt cell which energizes the salt water with a low voltage current; combining the salt with hydrogen to produce a usable sanitizer.

Unlike UV and ozone systems, the amount of sanitizer that the system produces can be controlled on your hot tub control panel. This allows you to vary your sanitizer level to match your usage and water temperature; making salt systems the only sanitization system able to run without chlorine or bromine also being used to supplement the sanitization process. It is not, however, able to oxidize the water so you will still need to regularly shock the hot tub.

Salt systems will also affect the balance of your hot tub water and requires you to maintain a consistent level of salt in your hot tub water. For this reason, some people find them to be a little more work to maintain than a standard chlorine or bromine hot tub.


Ionizers are one of the newer sanitization systems to hit the Canadian hot tub market. They work similarly to salt water systems by passing the water in the hot tub through a low voltage current. Rather than using this electrolysis to convert salt into sanitizer, however, ionizers use it to release copper and zinc ions (natural sanitizers) from a mineral electrode. Unlike salt systems, you’re also not able to vary the output of the system so you will still need to add some bromine or chlorine sanitizer to the water.

Ionizers provide effective sanitization when combined with chlorine or bromine. They do not oxidize organic materials, however. The mineral electrodes will also wear out over time and need to be replaced.

So Which Hot Tub Sanitization System Is Best?

All four of these systems have their own unique strengths and weaknesses, with no real clear winner between them. Fortunately, some manufacturers have begun to combine these technologies to make them even more effective. Hydropool Hot Tubs, for example, now offer their new Pure Water UV + O3 system. This system combines UV and ozone technology into one system to both sanitize and oxidize your hot tub water; dramatically reducing the amount of bromine or chlorine that your hot tub requires to maintain clean, clear water.

Wrapping Up

Sanitization and oxidation are both essential to the operation of any hot tub. While bromine and chlorine perform these tasks very effectively, they can also cause the water to feel “harsh” in higher doses. Fortunately, there are now several different sanitization systems available for hot tubs that can reduce the amount of these sanitizers that you need to add to the water; giving you a softer, more “natural” feeling water.

Each of these systems on their own have different pros and cons, making none of them the perfect solution. For this reason, some hot tub manufacturers have begun offering hybrid systems. These combine the benefits of multiple sanitization alternatives to create much more effective sanitization and oxidization systems that can greatly reduce the amount of chlorine or bromine that the hot tub requires.

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