What Are The Best Alternative Hot Tub Sanitizers?

Chlorine and bromine are definitely the most common sanitizers people use for hot tubs, but in case you’d like to find an alternative, we’ve got you covered.

Let’s get straight to the point, as there are several reasons why you might not want to use chlorine or bromine in your hot tub:

  • Chemical odor. This is probably the most common reason you’d choose to go the alternative route with your hot tub sanitizer. Bromine isn’t too bad in the smell department, but chlorine does put off a strong chemical smell that you may find annoying. The hot tub is a pretty small space, so even small amounts of chemical are going to put off a smell.
  • Bleaching. Excessive exposure to chlorine can start to discolor bathing suits and even hair. You may like to wear just plain old shorts and tee shirts in the hot tub, which sometimes makes that bleaching effect undesirable. 
  • Chemical sensitivity. Lots of people are sensitive to chlorine, but some can also be allergic or more sensitive to bromine than others. Sanitizing chemicals can leave your skin, hair and eyes dry and damaged, and can cause itching and burning and redness. Who wants to deal with that after taking a relaxing soak?

Why Sanitize At All?

But remember: you can’t give up sanitizing your hot tub altogether.

If you did that, you’d have worse problems than itchy skin!


Without sanitizer, your hot tub can harbor some pretty harmful bacteria including Pseudomonas aeruginos, Mycobacterium avium, and Legionella.

These are almost as scary as they sound. Respectively, they cause folliculitis, hot tub lung and Legionnaire’s Disease.

The only way to get out of sanitizing your hot tub would be to drain it and clean it out every time you use it, and only fill it up right before every use. 

Who has time for that?

The 5 Best Alternative Sanitizers

Luckily, even if you can’t or don’t want to use chlorine or bromine, there are some pretty great alternatives.

#1. Biguanides

Biguanides, or polyhexamethylene biguanide (PHMP), as the scientists call it, is an “effective microbe killer.”

Apparently, medical professionals used to use it in gauze dressing for wounds because it is good at pulling in all the bacteria and destroying it. 

There are some specific benefits of using biguanides in hot tubs.

For one thing, it doesn’t break down with high temps like some other chemicals.

And a lot of hot tub owners also prefer it since it doesn’t have that chemically smell like chlorine.

It also seems to make a difference in how the water feels, as most people think the water feels softer with it, and it’s also much gentler on the eyes and skin than chlorine as well.

But, of course, there are a few downsides too. 

For example, you cannot use biguanides with chlorine or bromine because they don’t interact well together.

But you still have to shock a biguanide hot tub regularly to keep it completely sanitized, you just have to use a shock without those two chemicals in it.

#2. UV

UV, or Ultraviolet purifiers sanitize the water by “permanently damaging the DNA of bacteria and other microbes that may be present, so they can’t reproduce.”

They work great for hot tubs because they kill the germs before they even think about spreading, but here’s the thing you need to know: you’ll probably still have to use some chlorine or bromine with them.

But it’s a great alternative to a fully chemical system because you can use a lot less of the chemicals than you normally would, which gets rid of a lot of that chemical odor and makes the water much gentler on the skin and eyes.

You’ll also still have to shock the hot tub occasionally, preferably with a chlorine or bromine shock to get the clarity of the water you probably want.

#3. Ozonators

Ozonators work by exposing oxygen to ultraviolet light to create a gas that destroys most bacteria in the water.

That ozone gas also breaks down all that oil and scum that people and products leave behind. 

Hot tub owners like ozonators because the effects last longer than chlorine or bromine and it’s about 3,000 times more powerful. So, the water stays cleaner and clearer longer.

You do still probably need to use some chlorine or bromine, but because you’ll require so little, you’ll hardly know it’s there. 

#4. Ionizers

Ionizers use a “natural water purification process called electrolysis”, which basically means there’s an electrode in the system that a very low voltage charge runs through that releases copper and zinc ions into the water, which destroys bacteria and algae. 

Ionizers are another sanitizing system that still require small amounts of chlorine to keep the water completely clean.

But these amounts are barely detectable, making it desirable for anyone who wants to use as little chemical as possible. 

#5. Salt Water Generators

Salt water systems are probably my number one pick for a chlorine or bromine alternative because of their ease of operation.

They’re also virtually odor-free and very gentle on the skin and eyes, which always helps.

Salt water hot tubs are not as “salty” as they sound; it’s not like ocean water where you can taste and smell the salt.

Pool Care Guy Tip

Water in a salt water tub contains less salt than that in a human tear, so it’s virtually undetectable. They also make the water feel much softer than regular chlorinated systems so they’re more soothing and comfortable to bathe in.

A salt water system contains salt cells that generate their own type of natural chlorine, so they’re just as effective as other types of chlorine when used right. 

And instead of replenishing your tub with liquid or granular chemical, you simply add salt to the water. Yep, it actually is good old fashioned table salt.

However, you can buy it in large bags and it is ground a little coarser for use in hot tubs and pools. 

Just like most other systems, it’s still a good idea to shock your hot tub once in a while to keep it completely germ-free and clear. 

Bottom Line

If you’d like to steer clear of chemicals in your hot tub, you do actually have some good options.

Most sanitizers still require that you add a shock treatment regularly, but with any of these, you can greatly cut down on how much of the chemicals you have to use. 

With any of these sanitizers, you’re definitely going to eliminate or at least drastically reduce the chemical smell and harshness to the skin.

The choice you make will probably just come down to the cost and maintenance required to make them work.

If you do decide to switch, it’s best to drain your hot tub completely and start all over with fresh waters to avoid mixing chemicals that shouldn’t be mixed, or decreasing the effectiveness of them.

They all have their own advantages and disadvantages, so just weigh them against your needs to pick one you like.

And as always, if you have any questions, drop us a line.

We are always happy to help!

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