Indoor Air Quality & The Hydraulic Connection: Solving the Winter Smell
As the temperature drops across Australia, indoor aquatic centres become the go-to hubs for fitness and hydrotherapy. However, the move indoors often brings an unwelcome guest: the sharp, eye-watering chlorine smell.
Many facility managers mistake this odour for an over-chlorinated pool. In reality, it is often a sign of exactly the opposite. Known as the winter smell, this phenomenon is a direct result of the hydraulic performance and chemical balance of your facility.
The Culprit: Chloramines and Off-Gassing
That distinct smell is actually the scent of chloramines (combined chlorines). These form when free chlorine reacts with organic contaminants like sweat, oils, and nitrogen-based compounds.
In an indoor environment, these chloramines don't just stay in the water; they become a gas and hang just above the pool surface—exactly where your swimmers are breathing.
Without proper hydraulic turnover and secondary disinfection, these gases build up, causing:
Eye and skin irritation for swimmers.
Respiratory discomfort, particularly for coaches and staff on the pool deck.
Accelerated corrosion of the building's infrastructure and metal fittings.
The Hydraulic Connection: Water Turnover is Key
Solving the winter smell starts with the skeleton of the pool. If your hydraulics are stagnant or poorly designed, dead spots occur where chloramines can concentrate.
At Trisley’s Hydraulic Services, (THS) we focus on ensuring your hydraulic turnover is optimised for the specific load of your facility.
High-performance pipework and meticulous pump calibration ensure that every litre of water is moved through the filtration system effectively, preventing the chemical pockets that lead to heavy off-gassing.
Secondary Disinfection: The Role of UV Chambers
While chlorine is essential for primary sanitisation, it often needs a partner to tackle the chloramine problem. This is where UV (Ultraviolet) Chambers become a game-changer for indoor facilities.
As water passes through the UV chamber in the plant room, the high-intensity light physically breaks down the chloramine bonds. This process, known as secondary disinfection.
Destroys the Winter Smell: By breaking down chloramines in the plant room, you stop them from off-gassing into the air.
Reduces Chlorine Demand: Because the UV system is doing the heavy lifting of breaking down contaminants, you can maintain safer, lower levels of free chlorine.
Targets Pathogens: UV is highly effective against chlorine-resistant microorganisms like Cryptosporidium and Giardia.
Beyond Compliance: A Healthier Winter Environment
At THS, we have installed and maintained state-of-the-art UV systems and hydraulic plants for some of Australia’s most high-traffic indoor centres.
Our team of experienced technicians—many of whom are ex-operators—understand that air quality is just as important as water clarity.
Through our Preventative Maintenance Agreements (PMAs), we carry out regular check-ins on your chemical controllers and UV systems to ensure they are calibrated correctly for the winter bather load.
We provide detailed reports with photos, giving you the peace of mind that your facility’s air and water quality are meeting the highest standards.
Don’t let the winter smell drive your customers away. Let the experts at Trisley’s Hydraulic Services audit your hydraulics and disinfection systems to ensure a fresh, healthy environment all season long.