How to Choose The Right Spa Sanitiser for Your Spa
Understanding Domestic Spa Sanitisers: Bromine, Polyhexanide Hydrochloride (Spa Sanitiser), and Hydrogen Peroxide (Poppits)
Keeping a home spa or hot tub safe, clean, and pleasant to use requires a reliable sanitiser to control bacteria, viruses, and organic contaminants. While chlorine & bromine remain common, many spa users seek gentler alternatives due to skin sensitivity, odour, or environmental concerns.
This article explores three options approved for use in Australia: Bromine, Polyhexanide Hydrochloride (sold under brands such as Aquafresh Spa Sanitiser), and Hydrogen Peroxide,(sold as Poppits Sanitiser or Peroxsil 395), highlighting how they work and how they compare.
1. Bromine
What is it?
Bromine is similar to chlorine and is commonly used in spas due to its stability at high temperatures and it operates better at higher pH levels which are often found in spas.
How It Works:
Bromine sanitises by oxidising contaminants and forming bromamines, which unlike chloramines rare excellent sanitisers. It is often dispensed in tablet form via a floating feeder or granules which are manually dosed.
Like all sanitisers you need to check and maintain within a safe range. Bromine can be corrosive if levels are allowed to remain high. This can lead to issues with the internals of equipment in particular pumps and the heat exchangers especially gas heaters and like all the sanitisers, too high is not safe for bathers either.
2. Polyhexanide Hydrochloride (PHMB)
What is it?
Polyhexanide Hydrochloride is an antimicrobial compound used as a disinfectant and antiseptic in many circumstances such as medical and wound care applications. PHMB is also used as an ingredient in some contact lens cleaning products. In the spa industry, it has been sold under the name Baquacil and brand names like Aquafresh Spa Sanitiser. PMBH is a liquid and offers a chlorine and bromine free approach to water treatment.
How It Works:
This sanitiser works by disrupting the cell membranes of bacteria, effectively killing them. It is not an oxidiser so it is paired with a non-chlorine oxidiser, Potassium Monopersulphate (Spa Shock)to remove organic waste.
It is non-irritating to skin, eyes and respiratory system and has no discernable odour. It is not compatible with Chlorine or Bromine so it is recommended to drain and refill the spa before use if either have been used previously.
PHMB is relatively easy to maintain, it is added with a weekly routine along with a clarifier and oxidiser. And it is recommended to shock with a non-chlorine oxidiser after each spa use. While it is not as corrosive a Bromine or Hydrogen Peroxide, like all sanitisers the level needs to be maintained within a specific range.
3. Hydrogen Peroxide (H₂O₂)
What is it:
Hydrogen peroxide (H₂O₂) is a strong sanitiser and oxidiser used in some natural spa systems. Though not a primary sanitiser on its own, it plays a key role when combined with agents like Spa Shock. In Australia it is sold under brand names such as Poppits Sanitiser or Persoxsil 395.
How It Works:
Hydrogen Peroxide breaks down organic waste and dead bacteria decomposing into water and oxygen leaving no chemical byproducts or odour. In Australia, the Poppits Brand is endorsed by the National Asthma Council of Australia as a “Sensitive Choice” product. This makes it a good choice for individuals with sensitive skin or respiratory issues and it’s valued for being non-toxic and environmentally friendly.
Like PHMB it needs to be used in conjunction with a non-chlorine shock treatment such as Poppits Quick Fix. Hydrogen peroxide is short lived and breaks down quickly in warm water, so it needs regular testing and dosing to ensure your spa stays healthy and safe to use.
Hydrogen Peroxide is corrosive so high levels can cause issues for bathers and equipment issues the same as Bromine.
And like PHMB, Hydrogen Peroxide is not compatible with Chlorine or Bromine so it is recommended to drain and refill the spa before use if either have been used previously.
Choosing the Right Spa Sanitiser
When selecting a sanitiser for your spa, consider your personal sensitivities, maintenance preferences, and system compatibility.
If you’re looking for a stable, highly effective sanitiser that performs well in hot water, Bromine is a strong choice. Those with sensitivities or who want a chlorine & bromine free alternative can consider either Polyhexanide Hydrochloride (Aquafresh Spa Sanitiser) or Hydrogen Peroxide (Poppits Sanitiser or Persoxsil 395)
Before switching systems, to a non chlorine or bromine alternative it’s essential to drain and clean your spa thoroughly (if either has been used previously) to avoid unwanted chemical reactions.
