The Ultimate Guide on How to Keep Your Hot Tub Water Clean

Clean, long-lasting water comes from preventing problems before they start, not correcting them after. Balanced water needs less sanitizer. A simple routine, guided by regular test strip readings, keeps water comfortable for bathers and easier on the materials. The result is water you change quarterly rather than weekly.

This guide covers the parameters, the treatment sequence, filtration, the products, caring for the materials, and using water responsibly. For how long a fill actually lasts, see how often you should change hot tub water.

Not sure where your water is right now? The Water Care Assistant takes your test strip readings and tells you what to correct, in what order. Free to use, and it works for any hot tub.

A different philosophy of water care

The conventional hot tub industry runs on a reactive model. Water gets contaminated, sanitizer kills the contamination, balance is restored. The assumption underneath is that the system will always be fighting bacteria rather than preventing the conditions that let it thrive.

That approach demands more input than it needs to, produces byproducts like bromamines that irritate skin and eyes, and creates a cycle where out-of-balance water needs increasingly aggressive intervention to recover.

An AlumiTub is structurally different. The smooth, non-porous aluminum interior has no banks of jets, no pipework and no hidden cavities where bacteria can establish. The simpler the design, the lower the baseline risk, and the less management the water needs.

Good Clean Living Water Care takes that further: purify at source before the water enters the tub, condition monthly to reduce organic load, and use bromine as a precision safeguard rather than a primary treatment.

Start clean. Stay balanced. Use less.

The four parameters

Parameter	Target	Why it matters	If it drifts
Alkalinity	80 to 120 ppm	Buffers pH and prevents rapid swings	Low, and pH fluctuates erratically. High, and pH resists adjustment
pH	7.4 to 7.8	Controls sanitizer effectiveness and bather comfort	Low irritates skin and corrodes. High makes sanitizer ineffective
Calcium hardness	150 to 250 ppm	Protects surfaces from corrosion and scaling	Below roughly 100 ppm the water is aggressive toward the aluminum
Bromine	2 to 3 ppm	Sanitizes the water	Below 2 leaves water unprotected. 3 is the ceiling

These interact. Alkalinity governs pH stability, and pH governs how well bromine works, which is why sequence matters. More detail in water chemistry for an aluminum hot tub, and parameter by parameter in the Water Care Academy: alkalinity, pH, calcium hardness and sanitizer.

Testing and balancing

How often

Two to three times a week in regular use, and before every session if the tub is used periodically. Always retest before soaking: bromine can fall to zero between sessions with no visible change. How to test hot tub water covers reading a strip properly, where to take the sample from, and why old strips read low.

The sequence

1. Alkalinity first, to 80 to 120 ppm. Municipal water is often close but confirm rather than assume. Circulate fifteen to twenty minutes and retest.
2. pH second, to 7.4 to 7.8. Well water often arrives high. Add gradually, circulate, retest.
3. Calcium hardness third, to 150 to 250 ppm. Two tablespoons of Calcium Balancer raises hardness roughly 10 ppm per 500 gallons.
4. Bromine last, to 2 to 3 ppm. Circulate and retest before soaking. Never dose and step straight in.

Always dissolve treatments in a bucket of tub water first, and add one at a time. This matters most for the Calcium Balancer, since calcium chloride releases heat as it dissolves. On a Wood Fired tub without a pump, stir with a paddle.

Your fill water is the starting point for all of it, and it varies more than most owners expect. Your hot tub water source covers well, rainwater, softened and ocean fills, and how to fill a hot tub covers the first balance.

Filtration, and what it changes

Filtration is the single biggest variable in how long a fill lasts, and it is worth understanding what it does before you decide whether you need it.

Without it, water is managed entirely by chemistry and habit. With it, a pump circulates the water through a 50 micron sediment filter on a schedule, catching the fine debris that clouds water long before you can see it. That is the difference between a fill lasting around two weeks and a fill lasting three to four months.

On an Electric or Hybrid it is included as standard, along with the heating, and both run on timer schedules set from a touchpad or the Wi-Fi app. The whole system sits inside the cedar steps against the tub, concealed but reachable, so changing a filter or a part is a job you do by hand rather than a call-out.

On a Wood Fired tub, filtration can be added as a 120V plug-and-play unit that runs from a standard outlet or a modest solar setup, no hardwired connection required. It needs the optional compatibility ports, which are specified at the time of order and cannot be added afterwards, so it is worth deciding before the tub is built.

One thing owners often miss on a Hybrid: the filtration belongs to the electric side but does not care how the water got hot. Heat entirely with wood all season and the filter and circulation keep running, so you still get the longer interval.

Filtration reduces how much work the chemistry has to do, but it does not replace it. The four parameters still need holding, and the filter itself needs cleaning on a schedule rather than when the water looks wrong.

Why there is no UV or ozone

No UV or ozone needed. Most spas fit them to reduce sanitizer demand, because jets and internal plumbing give water places to sit. An AlumiTub has neither. Keep the water in range and demand stays low on its own.

There is a chemistry reason as well. An aluminum interior calls for bromine, and bromine is the sanitizer both systems interact with badly: UV breaks it down as water passes through, converting active sanitizer back to an inactive form, and Health Canada advises against pairing bromine products with ultra-violet or ozone devices. Fitting one would mean designing a conflict into the tub.

Does your hot tub need UV or ozone? sets out the full reasoning, including what to do if your existing tub already has one.

The Good Clean Living routine

At source, before filling

The Purifier attaches to the hose before filling, removing heavy metals, chlorine from municipal supplies, fluoride, hydrogen sulfide and VOCs before the water reaches the tub. Flush it for a minute first and do not let it dry out between fills.

Monthly

The Stabilizer goes in once a month after use. This enzyme-driven treatment reduces organic load, steadies pH and alkalinity, and lowers how much bromine the water needs. Circulate fifteen to twenty minutes to distribute it.

Filter care

Check the canister weekly. Every two weeks, deep clean with the Filter Cleanser: two capfuls in a bucket, soak two hours or overnight, rinse thoroughly. Never soak the filter in the tub. Between cleans, add two capfuls of Filter Booster to the canister monthly. A spare filter keeps the tub in service while one is drying.

Soaking rather than hosing is the part that matters, because a hose removes surface debris and leaves the oils bound into the media, which is what actually restricts flow. Cleaning a hot tub filter properly covers the method and when a cartridge is finished.

Every three to four months

1. Empty fully using the drain kit
2. Clean the aluminum with a soft cloth. Never abrasive, never pressure washed, never vinegar
3. Clean cedar with a soft-bristle brush
4. For a deeper clean use the Tub Cleanser. Wipe while still wet, never let it dry on the tub, rinse thoroughly
5. Refill through the hose filter
6. Balance from alkalinity through to bromine before soaking

Draining and refilling a hot tub covers the order, where the water should go, and why a wood fired firebox has to be completely cold first.

The (Aroma) Therapist

A spa-grade eucalyptus mist, sprayed over the water surface before getting in. It adds nothing to the chemical load. Note that eucalyptus oil is flammable, so keep it away from an open firebox.

Caring for the materials

The aluminum interior

Non-porous and easy to clean. No abrasive pads, no pressure washing, no bleach or chlorine-based products, and no vinegar. A soft cloth with a mild plant-based cleanser handles routine work.

Keeping hardness in range is the primary way to protect the aluminum long term, because water that is too soft is corrosive to it.

The cedar

A soft-bristle brush and a rinse. Avoid leaving base boards in standing water or letting soil build against them. Silvering over time is the wood aging, not failing. On a new tub, expect brown water from cedar tannins for roughly the first five fills, and add no sanitizer until it clears: cedar tannins and brown water explains why that one matters.

The firebox

Empty ash every few fires with the scoop provided. A clean firebox draws better and burns more efficiently. Never drain below the fill line until it has fully cooled.

The equipment housing, on an Electric or Hybrid

Keep the cedar steps clear of leaves and debris so air can move around the heater, pump and filtration inside. Everything in there is concealed but reachable, which is what keeps servicing a hand job rather than a service call.

Anodes

Three magnesium anodes sit alongside the protection built into the tub, as an added safeguard against galvanic corrosion. They are fitted on Electric, Hybrid and Wood Fired with filtration, and are optional on a Wood Fired without it.

Replace them every three to four months, or once 30% or less of the anode remains. The specification is R-1-MG rudder and trim tab anodes, 1 and 7/8 inch. More in sacrificial anodes in an aluminum hot tub.

For cleaning the tub itself rather than the water in it, see how to clean a cedar hot tub.

Bather hygiene, the most underrated step

No treatment routine compensates fully for what arrives on people. Sunscreen, body oils, detergent residue and skin cells are the main causes of water clouding faster than it should.

• Rinse off before entering, and exfoliate where you can
• Rinse your feet before stepping in
• Skip lotion, sunscreen and oils before a soak
• Wash swimwear without heavy detergent, or rinse it thoroughly first
• Keep food and drink out of the water
• Skim debris off the surface after each session

When something goes wrong

Most water problems are one of a handful, and each has a cause worth identifying rather than treating blind.

• Cloudy water is usually balance, a saturated filter, or exhausted sanitizer
• Foam is surfactants, and often low calcium hardness rather than dirt
• A strong smell usually means too little active sanitizer, not too much

And when correction stops working, stop correcting. When to change hot tub water instead of treating it covers the point at which a fresh fill costs less than another round of product.

Conserving water and draining responsibly

Extending the time between changes is the most effective conservation practice available. Keeping the lid on reduces evaporation, slows chemistry drift and keeps debris out.

• Untreated water, including a fresh fill or an ocean fill from a natural source, can go to garden beds or back to where it came from
• Treated water must be neutralized before draining near plants, soil or waterways
• Ocean fills are changed every five to seven days rather than left standing, and the tub is rinsed between fills

Not sure where your water is? Check your readings with the Water Care Assistant, or browse the full Water Care Academy.