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Hot Tub Chemicals: Your Comprehensive Guide to Proper Usage

Posted by Watson's on Jun 9, 2023 3:00:00 PM

Clean, fresh water is the cornerstone of an enjoyable hot tub experience. Regardless of the number of seats or massage jets your spa boasts, murky water can ruin the experience. Regular chemical or salt maintenance is essential to maintain water quality and safety.

This guide covers the basics of hot tub chemicals and provides step-by-step instructions to help you maintain pristine water in your spa.

Couple Lounging In Clean Hot Tub

What Chemicals Do You Need for a Hot Tub?

To keep your hot tub in good condition, you'll need the following chemicals:


Chlorine is the most common sanitizer for hot tubs and swimming pools. It effectively kills bacteria and other harmful microorganisms in the water.


Bromine is an alternative to chlorine, especially beneficial for those sensitive to chlorine's smell. It has longer-lasting effects but is slightly more expensive.

pH Increaser & pH Decreaser

pH measures how acidic or alkaline the water is. Maintain pH levels between 7.2 and 7.8 to ensure optimal water quality.

Alkalinity Increaser & Alkalinity Decreaser

Total Alkalinity (TA) buffers pH levels, preventing dramatic changes. Maintain TA levels between 80 and 120 ppm for stable water chemistry.

Calcium Hardness Increaser

Calcium hardness measures dissolved calcium in the water. Maintain levels between 150 and 250 ppm to prevent corrosion of hot tub components.


For saltwater spas, salt replaces bromine and chlorine, offering a gentler option for sensitive skin.

Hot Tubs Chlorine and Chemicals

How to Add Chemicals to Hot Tub Water

Adding chemicals to your hot tub is straightforward but must be done correctly for maximum effectiveness. Follow these steps:

  1. Test the Water: Use a test kit to check pH, TA, and sanitizer levels.
  2. Adjust pH and Alkalinity: Add the necessary pH or Alkalinity increaser/decreaser to balance the levels.
  3. Add Sanitizer: Follow the manufacturer's instructions to add the appropriate amount of sanitizer.
  4. Wait and Retest: Allow 30 minutes or as directed for chemicals to dissolve, then retest the water.
  5. Enjoy Your Hot Tub: Once levels are balanced, you can safely use your hot tub.

Important: Never mix chemicals directly in the hot tub water. Dissolve them in a bucket of water first, then add the solution to the spa.


In What Order Should You Add Hot Tub Chemicals?

The order in which you add chemicals is crucial for their effectiveness:

  1. Alkalinity Increaser/Decreaser
  2. pH Increaser/Decreaser
  3. Calcium Hardness Increaser
  4. Sanitizer

Adding chemicals in this order prevents imbalances and ensures maximum effectiveness.

It is important to follow this order for maximum effectiveness. If you add the chlorine or bromine too early, it can cause the pH levels to shift, making them less effective.

Checking Hot Tub Chloring With Test Strip

Shop for Hot Tub Chemicals at Watson's

If you’re looking for hot tub chemicals or have any questions about the hot tub chemical process, Watson’s has everything you need.

When you shop with us, you’ll find an amazing selection and personalized service, along with the guaranteed lowest prices in the USA. We offer all the furniture you need for your outdoor spaces along with tons of pool and spa supplies to make your home stand out. Shop online or stop by your nearest Watson’s location today.


Frequently Asked Questions

Do you need to add shock after filling a hot tub?

Yes, you should shock your hot tub after filling it with water. Simply add the recommended amount of oxidizing shock solution to the water to eliminate any bacteria or other impurities that may have entered your hot tub during the filling process, as per the manufacturer's instructions, and wait for it to dissolve. Once it's dissolved, run the filtration system for four hours or as instructed by the manufacturer.

Can you go in a hot tub without chemicals?

Don’t go in a hot tub that hasn’t been treated with the proper chemicals! 

Chemicals are used to keep the water clean and free from harmful bacteria and other impurities. Going in a hot tub without the proper chemicals is not only unsanitary but can also cause skin irritation and other health problems.

If you own a saltwater spa then it won't require bromine and chlorine to keep it clean but you will have to test the water to ensure the salt levels are balanced.

How soon can you use a hot tub after adding chemicals?

You should wait at least 30 minutes after adding chemicals before using your hot tub. This will give the chemicals enough time to dissolve and distribute evenly throughout the water.

How long do hot tub chemicals last?

The lifespan of hot tub chemicals varies based on how often you use them and factors like temperature, sunlight exposure, and filter operation. 

Generally, chlorine or bromine granules can last up to two months before requiring replacement. Test strips and liquid chemicals have a shorter lifespan, typically lasting up to six months. 

It's important to store your hot tub chemicals in a cool, dry place and away from sunlight to help them last the longest. Avoid storing them under the hot tub or in the pump area, as this can affect their potency.

Topics: Spas and Hot Tubs, Spas and Hot Tubs - Supplies and Equipment

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