Understanding Hot Tub and Spa Chemistry

Understanding Hot Tub and Spa Chemistry

Hot Tub Chemistry 101

From Swim University

If you are a hot tub owner, you have realized by now that a hot tub is a much different animal than a typical swimming pool.  The super heated water along with the smaller gallonage makes for a cauldron of bacteria, and makes it difficult to keep chemistry in balance.  Where else would you turn to for a basic lesson in Hot Tub Chemistry other than Swim University?  This post from Matt Giovanisci provides a blog post called Hot Tub Chemistry 101, which is indeed a great primer on hot tubs and chemistry for the DIY’er.

Here is an excerpt from the post:

A hot tub is a large investment – much like purchasing a car – and you want your investment to last as long as possible. You want the people who use it to be safe, which is why you need hot tub chemicals. Keeping your hot tub clean and sanitized is not only important for your tub, but it’s also important for the people in it.

Let’s take a look at some of the chemicals that you NEED for your hot tub.


You have to decide on which type of sanitizer you will use.

Salt System
Baquaspa (Biguanide)
1. Chlorine: The most popular water sanitizer
granular-chlorineChlorine is an excellent sanitizer for your hot tub. However, chlorine mixed with hot, steamy water can create an unpleasant chlorine smell, which is why some hot tub owners stay away from this chemical.

There is a reason behind the chlorine smell. When chlorine goes into your water and attacks bacteria or algae, it dies – just like certain bees when they sting you. That dead chlorine is then gassed off which is called oxidation. That means, when you smell chlorine, it’s not in the water – it’s in the air.

Click here to read the entire post