Built for the long haul, and backed like it
Over 10,000 AlumiTubs are out in the world, at off grid cabins, lake cottages, family homes and coastal properties across the globe. The earliest ones are still being soaked in today.
Coastal salt air. Minus forty in the north. Hard well water. Rentals running seven days a week. Cabins left alone through the winter. The design has been refined over twenty five years of tubs coming back to us with real world wear from real world places.
That track record is why we can put a 25 year structural warranty on a hot tub, and why every component is replaceable rather than disposable.
Why aluminum, and how it is protected
Marine grade aluminum was chosen because it holds up where other materials don't. It doesn't rely on swelling to stay watertight the way a traditional cedar tub does, and it doesn't crack or delaminate the way molded acrylic does. Cedar stays on the outside where it belongs, doing what it's best at.
Aluminum is also a metal, and every serious marine application manages that the same way: the right alloy, sacrificial anodes where they're needed, and water kept within a defined range. Boat hulls have been built this way for a century. We've built this way since 2001, and it's why so many of those early tubs are still in service.
The structure is riveted rather than welded, the way aircraft and Airstreams are built. Welding aluminum softens the metal along every joint. Riveting keeps the full strength of the alloy at each one, and a rivet can be replaced by hand decades later. Riveting takes longer and costs more. It was chosen because the tub has to outlast the person who bought it.
The water is what protects it
Aluminum protects itself with a thin oxide layer that re-forms continuously on contact with oxygen. It is what makes aluminum last on boat hulls and aircraft skins for decades, and it is why a twenty year old AlumiTub is still in service.
That layer is stable across a wide range of conditions and unstable at the extremes. Keep the water in range and it looks after itself. Let the water sit well outside range for a long period and the surface will eventually show it.
So water care is not a maintenance chore bolted onto the tub. It is the protection. Four numbers, corrected in order, and the tub looks after itself from there.
Water care ranges
| Parameter | Target |
|---|---|
| Total alkalinity | 80 to 120 ppm |
| pH | 7.4 to 7.8 |
| Calcium hardness | 150 to 250 ppm |
| Bromine | 2 to 3 ppm |
Correct them in that order. Each one affects the ones after it, and correcting sanitizer before the first three mostly wastes product.
Know your fill water as well as your readings. What comes out of the tap, before anything is added, sets the starting point. Hard water is brought into range by blending as you fill. A tub filled through a water softener, or with rainwater, starts low on calcium and needs raising to 150 to 250 ppm on every fill.
How treatments go in matters too. Dissolve powder balancers in a bucket of warm water or add them through the filter canister, rather than pouring them onto the tub floor, where concentrated product can settle against the surface.
Bromine is distributed by a dispenser rather than added by hand: an in-line dispenser on Electric, Hybrid and Wood Fired with Filtration tubs, and a floating dispenser on tubs without filtration.
Not compatible with an aluminum interior: chlorine in any form, pucks and floaters, salt chlorine generators, copper based algaecides, silver based mineral cartridges. Several of these are standard in the acrylic spa world, which is why pool stores recommend them.
Sacrificial anodes
A sacrificial anode is a block of a more reactive metal placed in the water so it corrodes preferentially. Standard practice on boats and in water heaters for as long as either has existed.
Magnesium is used because the anode has to be more reactive than aluminum to do anything at all. Electric, Hybrid and Wood Fired with Filtration tubs run three magnesium anodes, replaced every 3 to 4 months, or once 30% or less remains. That falls naturally alongside a seasonal deep clean.
One thing worth knowing: an anode only works if it is bolted to bare metal with genuine metal to metal contact. Mounted on cedar, or on a painted surface, it looks like protection and provides none.
Bonding on Electric and Hybrid tubs
Like any hot tub with electrical equipment, an Electric or Hybrid AlumiTub is bonded by a licensed electrician to local code. The one detail specific to aluminum is the connector: anything that lands on the aluminum must be rated for aluminum (AL/CU), never brass or plain copper. The one-page AlumiTub Electrician Reference sets it out for your electrician.
Know your water before you buy
The single most useful thing you can do is find out what your fill water actually is, and that is free.
Our water care tool takes your test readings and tells you what to correct, in what order, and builds a maintenance schedule you can keep on your phone. It works for any hot tub and needs no account. If you are on municipal water, your supplier publishes an annual quality report with the calcium figure for your area.
Or email hi@alumitubs.com with your location and water source and we will tell you what your water will need, before you buy rather than after.
Good Clean Living Water Care
Rather than leave owners to assemble a compatible routine from a pool store shelf, we put together Good Clean Living Water Care, a curated collection built specifically around aluminum and around the ranges above.
Fill purification, balancers, a monthly plant derived stabilizer, filter care, and a deep clean every 3 to 4 months. Everything in it is compatible with an aluminum interior, so there's no cross checking labels and no guessing about whether something belongs in your tub. It works by reducing what your water needs rather than adding more to it.
What it looks like after a decade or two
The most useful evidence isn't ours. These are owners describing tubs they have lived with for years, in their own words.
We have happily been using our AlumiTub for nearly 20 years. Thank you for building such a remarkable product. I can't tell you about the countless happy hours we have spent in its warm confines.
Heidi and Bruce Reugg
We got our tub in 2015 and installed it ourselves at our island cottage.
Lorne and Tanya Atkinson, island cottage, Ontario
We have been enjoying our hot tub for the last year. Purchased in April 2016. Even kept it burning through the minus 30 C nights of Alberta winters.
Mitch and Sherry Metrunec, Alberta
Brought our family together. My kids come up to the cabin just to use the hot tub. It's our family staple and we've loved it for 8 years now.
Metallier
After barging our AlumiTub over to our wildfire-burned lot on Loon Lake 7 years ago, two of us rolled it up the hill and installed it. Maintenance and upkeep have been easy. The AlumiTub is built to last and we expect several generations to enjoy it over the years.
Gail Hunt, Loon Lake
We've had our tub 4 or 5 years and absolutely love it. On a remote site in Northern Manitoba.
Rob and Kate Buchanon, Northern Manitoba
We have had our Alumitub for 3 years and think it is the greatest thing ever!
Rick Wirthlin
I was always a little hesitant of going with one that was only cedar because of how it would last over time with the winter/summer cycle and the wood constantly expanding and contracting. That's when I found AlumiTubs, and it was the perfect solution. It has already survived a harsh winter with no issue.
Scott Hauser, upper Midwest
It feels much more durable than the wooden hot tub we had before. Sturdier construction, better insulation, and no concerns about leaks or warping.
b cramer
What we put behind it
A 25 year structural warranty. The marine grade aluminum structure and foundation, together with the stainless chimney, cap and bands, are warranted to remain free of leaks for twenty five years from delivery. Registered automatically when your tub ships, with no form to fill out.
A tub that can be worked on. Nothing is buried. On most hot tubs the working parts sit behind sealed panels and packed foam, awkward to reach and sometimes impossible, which is what eventually decides whether a spa is repaired or thrown away. On an AlumiTub the cedar, the firebox, the heater, pump, board and filtration are bolted, banded or slotted onto the aluminum structure, so any of them can be reached and replaced by hand.
Nowhere for water to sit. There are no banks of jets and no internal plumbing, so there is no cavity inside the tub that a drain and rinse doesn't reach. On the Electric and Hybrid, heating and filtration live outside the tub in the cedar steps. That is what keeps sanitizer demand low, and it means emptying the tub completely is a matter of opening the drain valve every AlumiTub comes with.
A tub that changes with you. Because the heating system is modular rather than integral, it can be swapped entirely. A wood fired tub can take electric heating and filtration years later. A hybrid can run either source, or both. The tub adapts to a new property, a new climate or a different way of living, instead of being the wrong tub for it.
And parts for the life of it. Every component is replaceable and available to buy, including on tubs well past their coverage period and on tubs bought secondhand. We still supply parts for tubs built two decades ago.
If you already own one
If you've seen a surface change you're unsure about, email hi@alumitubs.com with photos, your order number and your four water readings from a liquid test kit, and on Electric and Hybrid tubs, how the tub is bonded. Surface changes have more than one possible cause, so we work through them with you rather than guess. Any buildup can be worked off gently with a plastic paint scraper; never use a metal blade, an abrasive pad or sandpaper. We support owners regardless of how old the tub is or whether they bought it from us.
Everything we've published on this
If you're researching aluminum before buying, these go into more detail than we can here. We'd rather you read all of it.
- What causes pitting in an aluminum hot tub? What gets called pitting, the five places to look in order, and what to send us if your tub shows it.
- Do aluminum hot tubs corrode? The short answer, a comparison with stainless, acrylic and cedar, and what protects the tub.
- Water chemistry for an aluminum hot tub. The four numbers that matter, what order to balance in, and which common spa products aren't compatible.
- Sacrificial anodes in an aluminum hot tub. What they do, why magnesium, how often to replace them, and the four things anodes can't fix.
- Does your hot tub need UV or ozone? Why we don't fit either, and what does the same job.
- Hot tub materials compared. Aluminum, cedar, acrylic and plastic, including where an aluminum tub isn't the right choice.
Still weighing it up? Email hi@alumitubs.com with your location and water source and we'll tell you honestly whether an aluminum tub suits your property. We'd rather talk someone out of the wrong build than sell the wrong one.