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Can you use salt water in a wooden hot tub?
We regularly get the question whether you can use salt water in Western Red Cedar hot tubs. For a Northern Lights hot tub, we advise against it.
The cedar itself is not necessarily the main concern. Salt can cause problems for the metal and technical components in your hot tub, especially your heating system. It’s thought that salt water reduces the need for maintenance products, but adding salt alone does not disinfect your water.
If you are looking for an alternative way to maintain clear and fresh water, there are better options that are designed to work with your hot tub.
Does salt water disinfect your hot tub?
Adding salt to tap water does not automatically turn it into disinfected water. Saltwater pools and spas generally use a saltwater electrolysis system. The dissolved salt passes through a generator that converts chloride into active chlorine. This process is referred to as “salt water chlorination”. It is the thus generated chlorine that disinfects the water, rather than the salt itself.
Salt and metal are not a good combination
The bigger issue appears once salt water starts circulating through your hot tub system. Your hot tub contains several metal components in its heating and circulation system. Salt increases the electrical conductivity of the water and creates conditions where corrosion can occur. In a system containing different metals, the less noble metal is generally the first to corrode.
Over time, this affects heaters, pumps, connections and other metal components that come into contact with the water. That is why equipment intended for salt water needs to be specifically designed for it and clearly advertised as such.
What can you use instead of salt?
If the appeal of salt water is that you would like to rely less on traditional water treatment products, there are much better natural alternatives.
One possibility is UV-C water treatment. As the water circulates through the system, it passes a UV-C lamp that inactivates bacteria and other microorganisms in the water. It is an effective way to support your regular water maintenance without adding salt to the tub.
An even better mineral-based approach is with an mineral ionizer like the ClearBlue Ionizer. This system releases controlled amounts of copper, silver and zinc ions into your hot tub water. Copper and silver help control microorganisms, and because these mineral ions remain present in the water, their effect is not limited to the moment the water passes through the system. Zinc adds to the mineral composition of the water and contributes to the softer water feel associated with ionisation.
You get the advantages of a mineral-based water treatment system without circulating salt water through your heating system, pumps and other components.
A better match for your cedar hot tub
When you look at how a saltwater system actually works, it is not as straightforward as replacing your usual water treatment with a few scoops of salt. A salt electrolysis system still produces chlorine, which is very damaging to cedar, while the salt itself creates a more corrosive environment for the metal components in your installation.
That is why at Northern Lights we offer water treatment systems that work well with both the Western Red Cedar and the technical installation, while also being natural and chemical free. UV-C kills bacteria using ultraviolet light, while copper, zinc and silver ionisation provides a more comprehensive solution for natural, chemical-free water treatment in your hot tub.
If you are unsure which water treatment system is the best fit for your situation, contact us and we can help you choose the right solution.
To read more about the use and benefits of UV-C and Ionisation, explore our maintenance page.
