Understanding Hot Tub Chemicals: A Comprehensive Guide

Written by: Jake Riggs



Time to read 4 min

You finally got that hot tub you've always wanted! Can you fill it with water, start soaking it, and use those massaging jets? You could do that, but it wouldn't be a good idea. Like a swimming pool, your hot tub needs chemicals to keep the water clean, crystal-clear, and algae and bacteria-free. 

You must regularly maintain your hot tub to keep it safe for soaking. In this article, you'll find a comprehensive guide to understanding hot tub chemicals, what they are, and when to use them.

Test the Water First

Before adding any spa chemicals, you want to test your water with at-home test strips.

This is how you'll learn where your chemicals could be improved and what you need to add. There are, however, hot tub chemicals that you want to have on hand because you will use them regularly. 


The most important chemical for your hot tub is sanitizer. Now, there are several types of sanitizers that you can add to your hot tub, and you need first to decide which one you want to use.


Most people use chlorine to sanitize their spa water. Why? It's not only cost-effective, but you can add it easily. Moreover, chlorine kills bacteria and algae in your hot tub water.

Remember, your spa is a body of warm water, so you want to stay on top of your chlorine usage so your hot tub stays healthy. The best chlorine level for your hot tub is between one and three parts per million (ppm).


Bromine is your other choice for sanitizing your hot tub. It lasts longer than chlorine, and its pH is lower. So, keeping your water balanced is often easier than chlorine. Many people also find bromine to be gentle on your skin. 

It works more slowly than chlorine and needs to be stabilized. What does this mean? If you leave the cover off your spa, the bromine will quickly burn off under the sun.

If you use bromine, your proper levels are between three and five ppm.

Shocking Your Tub

Another must-have hot tub chemical is shock. This is necessary for keeping your hot tub clean and safe for swimmers. Hot tub shock, like SpaGuard Enhanced Shock, helps you eliminate contaminants from usage. 

For example, shock contains oxidizers that break down organic substances in your hot tub. If you have cloudy water or start to see algae, it's time to shock your hot tub.

SpaGuard Enhanced Shock also helps your filtration system identify and eliminate particles you don't want in your water.

SpaGuard Enhanced Shock works for all hot tub sanitization systems, including chlorine and bromine. We also like this shock product because it helps you avoid fluctuations in the pH balance of your spa.

Finally, shocking your hot tub weekly helps boost your sanitizer levels so you don't have any problems in the future.

Enhanced Shock for Spas
Enhanced Shock for Hot Tubs

Take Care of Alkalinity and pH Levels.

You must manage your total alkalinity and pH levels like a swimming pool. When you measure pH, you test how acidic your water is. We generally discuss total alkalinity and pH because alkalinity buffers your pH levels. You'll learn that alkalinity neutralizes acid and keeps your pH levels from flip-flopping from high to low.

Alkalinity affects pH, and pH affects alkalinity.

  • Keep your alkalinity level between 100 and 150 parts per million (ppm).
  • Keep your pH level between 7.4 and 7.6.

If your pH level gets too high, your bathers have burning eyes and itchy skin. If it gets too low, you may end up with corrosion in your hot tub.

We recommend keeping the alkalinity increaser, pH increase, and pH decrease on hand so they're ready when needed.

  • You need an alkalinity increaser if the total alkalinity in your water drops. When using the increaser, it also brings your pH level down.
  • You need a pH increase if your pH level drops. This chemical helps bring your pH back up, so bathers don't have burning eyes, and you don't end up with hot tub corrosion.
  • Use a pH decrease to lower your alkalinity and your pH simultaneously. You want to ensure your pH is manageable because you will also end up with cloudy water and sanitizer that doesn't work as it should.

Avoid Calcium Hardness with Spa Sentry

To avoid calcium hardness, use Spa Sentry. The last thing you want in your hot tub is soft water because it can cause problems with your spa's shell, pipes, and other equipment. A calcium hardness increaser can help. When you test your water, you want these levels between 175 and 250 ppm.

But what happens if your calcium hardness levels are too low? Drain your hot tub, clean it, and add new water and chemicals.

How to Maintain Your Hot Tub

Create a hot tub maintenance routine for the best results.

  • Sanitize once a week.
  • Use an oxidizer after you sanitize.
  • Test your pH levels one or two times each week. Add pH balancer when needed.
  • Cover your hot tub when not in use.
  • Clean the shell every month or so.
  • Add additional chemicals as your water test tells you.

Final Tips on Hot Tub Chemicals

Your hot tub should provide you with years of relaxation, wellness, massage, sore muscle relief, stress relief, and much more!

The health benefits are numerous, but you can only enjoy your hot tub if you practice regular maintenance.

So, use our comprehensive guide on spa chemicals to create a safe, soaking environment. You'll also prolong the life of your hot tub and save money because you'll have fewer repairs. Always use the highest quality hot tub chemicals, and don't scrimp!

Care for your investment; you'll enjoy it with friends and family for years. 

Have you got a hot tub, a swimming pool, or both? Great! You've come to the right place if you want quality hot tub and pool chemicals shipped to your door. At Pool Goods, we are here to help you enjoy every day in your hot tub with the best pool and spa products on the market shipped right to you!