You can run a hot tub without ever buying a jug of chlorine. Bromine does the same job through a different chemical. An ozone-primary system lets whatever residual you do carry be small enough that it barely registers. What you cannot do, no matter which route you pick, is run a hot tub with nothing in the water at all. Warm water with people in it needs a sanitizer on duty at all times, or bacteria get the run of the place.
So the honest question is not "chlorine or nothing." It is "which alternative, and how small can the residual actually get." Here is what each option really does.
Why "no sanitizer" isn't on the table
Every bather who gets in brings sweat, skin oils, lotion and bacteria with them. A hot tub is a small volume of warm water holding a lot of people relative to its size, which is exactly the environment bacteria multiply fastest in. Something has to be present in the water between uses to keep that in check. That something is a measurable sanitizer residual, whether it comes from chlorine, bromine, or the chlorine a salt cell manufactures on site.
That is true of every hot tub sold in Canada, ours included. The choice you actually get to make is which sanitizer carries the residual, and how much of the sanitizing work gets done by something other than that residual before it ever has to act.
The alternatives, compared honestly
Five approaches come up when people search for a way off chlorine. Only one of them removes chlorine specifically. The rest change how much sanitizer you need or where it comes from.
| Alternative | What it does | Stands alone? |
|---|---|---|
| Bromine | A different halogen sanitizer. More stable in heat than chlorine, gentler smell at a working dose, and it is the residual itself, not a booster. | Yes, on its own |
| Saltwater | Electrolysis converts dissolved salt into chlorine inside the plumbing. The sanitizer is still chlorine, just made on site instead of dosed by hand. | No, it is chlorine |
| Mineral cartridges | Silver or copper ions slow bacterial growth, which lets you run roughly half the usual chlorine or bromine level. | No, a supplement |
| Ozone | Oxidizes contaminants on contact in the circulation loop, about 3,000 times faster-acting than chlorine, then reverts to oxygen with no residue. | No, needs a small residual |
| Enzymes | Break down body oils and lotion so the sanitizer isn't wasted digesting them. Not a sanitizer at all. | No, a supplement |
Bromine is the one true swap. Everything else on that list either is chlorine in disguise, or reduces how much sanitizer you need without eliminating it.
Bromine: the direct alternative
If the goal is specifically "no chlorine in this water, ever," bromine is the answer. It is a halogen sanitizer like chlorine, but it breaks down more slowly at spa temperatures and does not produce the same sharp chloramine smell at a comparable working level. Owners who find chlorine harsh on their skin or eyes often switch to bromine and notice the difference immediately.
The tradeoff is that bromine is still a chemical you are dosing and testing on a schedule, same as chlorine. It does not reduce your maintenance routine or your chemical spend. It changes which chemical is in the bottle, not how often you reach for it.
Ozone: the residual shrinks, but it never hits zero
Ozone works differently from every other option on this page. Instead of holding a chemical level in the water to slowly kill things, ozone oxidizes contaminants the instant they pass through the circulation loop and then reverts to ordinary oxygen. Nothing accumulates and nothing lingers to irritate skin.
The catch is timing. Once an ozone molecule has done its job, there is nothing left in the tub as a barrier until the next circulation cycle. For that reason, a small sanitizer residual still rides alongside ozone in every system we know of, including ours. It is a backup net, not the primary defence, which is why it can be so much smaller than a chlorine-only setup requires.
That gap between "primary" and "backup" is the whole story. In a standard chlorine tub, the chlorine does 100% of the sanitizing. In an Eco Spa running Ecozone, ozone does the bulk of it and the residual only has to cover the space between cycles, which is why chemical use drops by about 90% and water care settles into roughly 15 minutes a month. Read the full breakdown in our ozone vs chlorine comparison.
Why saltwater doesn't actually get you off chlorine
Saltwater systems get marketed right next to bromine and ozone as a way to avoid chlorine, and that is where the confusion starts. A salt cell runs a current through salty water and splits it into chlorine, right there in the plumbing. The sanitizer sitting in your tub afterward is chlorine. You have changed where it comes from, not what it is.
That does not make saltwater a bad choice. The chlorine tends to be steadier since it is produced continuously rather than dosed in bursts, and a lot of owners genuinely prefer the feel. It just means saltwater belongs in a different category than bromine or ozone when the question is specifically "how do I get chlorine out of this water." Our saltwater vs chlorine guide covers the full comparison, including what salt does to a shell and heater over time.
What the shell has to do with any of this
Whichever sanitizer you pick, it has to fight harder on a porous shell. Acrylic holds microscopic pores where bacteria settle in and form biofilm, a layer no sanitizer, chlorine, bromine or otherwise, can fully reach. The residual keeps getting consumed re-fighting the same colony instead of handling what is actually in the water that day.
A one-piece HDPE shell has nowhere for that colony to anchor, so whatever sanitizer you are running only ever has to deal with what is freshly in the water. That is a bigger factor in how low you can push your chemical use than which sanitizer sits in the bottle. See why a non-porous shell resists bacteria for the mechanics.
What we run
Every Eco Spa can run Ecozone, our ozone system, as an upgrade, and it comes standard on the Deluxe models. Paired with the HDPE shell, ozone handles most of the sanitizing and the residual you carry stays small. We do not claim the residual disappears, because it does not, but it is the lowest-chlorine setup we can build. If bromine is what you are after instead, it runs fine in any Eco Spa too, the shell and filtration help it the same way they help ozone.
Either way, the weekly and monthly routine is short. Our maintenance guide lays out the full schedule, including the water chemistry targets, pH 7.2 to 7.8, alkalinity 80 to 120 ppm, calcium hardness 150 to 250 ppm, and a small steady sanitizer residual, that apply no matter which sanitizer you choose.
The bottom line
"Hot tub without chlorine" has a real answer: bromine, full stop, or an ozone-primary setup that shrinks whatever residual you carry down to a small backup. What it does not have is a version where nothing is in the water. Anyone telling you otherwise is skipping the part the owner's manual spells out. If you want the fuller picture on why there is no such thing as a chemical-free hot tub, start with our chemical-free hot tubs guide, or read how Ecozone is built into an Eco Spa.
Frequently asked questions
Can you run a hot tub without chlorine?
Yes, in the sense that you never have to buy or dose chlorine directly. Bromine is a full substitute, and an ozone-primary setup lets the residual you do carry be very small. What you cannot do is run a hot tub with no sanitizer at all. Something has to be in the water at all times to stop bacteria between uses.
Is bromine better than chlorine for a hot tub?
Bromine is more stable at hot tub temperatures and does not produce the same sharp smell as chlorine at similar doses, which is why many owners who find chlorine harsh switch to it. It is still a halogen sanitizer and still a chemical you are dosing. It is a genuine alternative to chlorine, not a step up in the way ozone is.
Does a saltwater hot tub avoid chlorine?
No. A saltwater system uses electrolysis to convert dissolved salt into chlorine inside the plumbing. The sanitizer in the water is chlorine either way. Saltwater changes the handling, salt added a few times a year instead of chlorine dosed weekly, but it does not remove chlorine from the equation.
What is the lowest-chlorine way to run a hot tub?
An ozone-primary setup on a non-porous shell. Ozone handles the bulk of the sanitizing and reverts to oxygen, so the residual sanitizer riding alongside it can be kept small instead of doing the whole job. In an Eco Spa with Ecozone that combination cuts chemical use by about 90%, down to roughly 15 minutes of water care a month.
Do mineral cartridges replace chlorine or bromine?
No. Silver or copper ions from a mineral cartridge slow bacterial growth and let you run a lower sanitizer level, often about half of what you would use otherwise. They are a supplement, not a sanitizer. You still need chlorine or bromine at a reduced dose alongside them.