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Maintaining the proper chemistry balance of your hot tub or spa is one of the most important steps you can take to ensure its optimal performance, as well as your safety and comfort. Understanding the basics of hot tub chemistry and when and how to add spa chemicals is essential for its overall health and longevity. In this article, we’ll provide you with an overview of hot tub chemistry, including what, when, and how to add spa chemicals.

1. What are Spa Chemicals

Spa chemicals are special cleaning and sanitizing agents designed to keep your hot tub or spa clean and safe. The three main hot tub chemicals are sanitizers, balancers, and water-cleaning agents.


These are used to lower bacteria levels in the water and reduce foul odor. Common sanitizers include chlorine, bromine, and biguanides.


These are used to ensure the water’s pH, alkalinity and total hardness levels remain within the optimal ranges. Common spa balancers include pH decreaser, pH increaser, bicarbonates, calcium, and chlorine neutralizers.

Water-Cleaning Agents:

These are designed to keep the water clean of oils and other contaminants.Common water-cleaning agents include clarifiers, foam reducers, algaecides, and enzyme cleaners.

2. When to add Spa Chemicals

The timing for when to add spa chemicals depends on several factors. Start by testing the pH and sanitizer levels every day or two, and add spa chemicals as needed to keep the water in these levels within the proper ranges. In addition, it’s generally recommended to shock the water once a week, regardless of the test results. Additionally, you should check the water chemistry after every use and adjust levels as needed.

3. How to Add Spa Chemicals

When it comes to adding spa chemicals, always make sure to read and follow the instructions carefully. In general, you should place the chemicals directly into the hot tub or spa, rather than mixing them with water and pouring in the mix. It’s also important to add the chemicals a few hours before you use the hot tub, as this gives it plenty of time to mix and balance. Lastly, always make sure to turn off the hot tub before adding any spa chemicals and wait until they are mixed and properly balanced before turning it back on.

4. People Also Ask

Q: How often should I test the spa water?

You should check and test the pH and sanitizer levels daily or every other day and adjust the levels as needed.

Q: Do I need to use spa chemicals?

Yes, using spa chemicals is essential for your hot tub or spa’s optimal performance and to ensure the safety and comfort of anyone using it.

Q: What is the standard amount of spa chemicals to be added?

The amount of spa chemicals to add depends on a variety of factors, such as the size of the spa, usage, and environmental contamination. Read the chemical labels carefully and follow the instructions provided.

Q: Is it safe to drink hot tub water?

No, it is not safe to drink hot tub or spa water as the levels of sanitizers and other chemical levels are typically much higher than the recommended levels for drinking water.

Q: What chemical should be added first?

It is generally recommended to adjust water balancing chemicals before sanitizing agents, such as adding pH increasers before chlorine.


Hot tub or spa chemistry is essential for the overall health and longevity of your hot tub or spa. Understanding what, when, and how to add spa chemicals will help ensure it is clean and safe for your use. Always make sure to read and follow the instructions on chemical labels carefully, and be sure to test the water regularly and adjust levels as needed.