Why does my hot tub smell like chemicals??

When your hot tub or spa has a strong chemical smell it is time to shock your water.  Chlorine breaks things down and becomes depleted doing so. It breaks down contaminants in the water that are introduced by the bathers including sweat, body oils and other human waste, and it breaks down things that are dissolved in the water like iron and copper.  When chlorine is depleted, it doesn’t just vanish, rather, it is converted to something called a chloramine (sometimes referred to as ‘combined chlorine’). All a chloramine does is give off that odour that people refer to as the chlorine odour.

​As another example, when you walk into a public pool and smell the “chlorine smell” and think “wow, they have a lot of chlorine in the water”, the opposite is true.  They have a lot of depleted chlorine (chloramines) in the water.

To get rid of chloramines, you need to shock the water.  Shocking is the process of adding a large dose of an oxidizing agent to the water, and oxidizing agents can be chlorine, bromine or spa shock.  In other words, if you smell chlorine, you can clear it up by adding more chlorine (or bromine or non-chlorine shock) to the water.

When chloramines are oxidized, they are converted to trichloramines, which are airborne, and you need to leave the lid open/cover off so that the trichloramines can escape into the air.

What if I use bromine?

Bromine breaks things down and becomes depleted doing so. It breaks down contaminants in the water that are introduced by the bathers including sweat, body oils and other human waste, and it breaks down things that are dissolved in the water like iron and copper.  When bromine is depleted, it doesn’t just vanish, rather, it is converted to something called a bromamine (sometimes referred to as ‘combined bromine’). All a bromamine does is give off that odour that people refer to as the bromine odour.

To get rid of bromamines , you need to shock the water.  Shocking is the process of adding a large dose of an oxidizing agent to the water, and oxidizing agents can be chlorine, bromine or spa shock.  In other words, if you smell bromine, you can clear it up by adding more bromine (or chlorine or non-chlorine shock) to the water.

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