Can I Use Chlorine Shock in a Bromine Spa? (Yes, if you do this)

Shocking your hot tub refers to adding a high dose of oxidizer to the hot tub water. This helps combat disease and other bacteria. But if you use bromine to sanitize your hot tub, you’ve probably wondered can I use chlorine shock in a bromine spa?

I decided to get to the bottom of it, and here’s what I learned:

Yes, it’s OK to use chlorine shock in a hot tub where bromine is your sanitizer. Just make sure to avoid mixing the two of them in their powdered form. Also, know that adding chlorine shock will raise the chlorine count in your hot tub, so always test the water before entering and wait if needed.

But there’s a lot more to know about the pros and cons of chlorine shock, how they interact with bromine, and what is the most cost-effective way to keep your hot tub water sparkling clean! So let’s keep going!

An oxidizer is a chemical that takes electrons from a particle when it encounters one. Basically, the oxidizer breaks down organic matter. This ensures your hot tub water is clean and safe to soak in.

Many people shock their hot tubs. They usually use bromine or chlorine. But you may be wondering all about bromine, chlorine, and the difference between shocking and using sanitizers.

Read on to find out.

What’s the difference between shock and sanitizer?

The biggest difference between hot tub shock and sanitizer is the strength of the chemicals. Shock has a much higher dose of chemicals, and is designed to reactivate the sanitizer, and is performed weekly as opposed to every few days.

A sanitizer, which is typically chlorine or bromine, is used to destroy disease-causing germs.

Hot tub shock, by comparison, can be chlorine or non-chlorine. When you sanitize water, it means you are removing bacteria from your hot tub.

The most common hot tub sanitizers are chlorine or bromine.

Shock is a bit different. Shocking involves using a concentrated dose of chemicals to increase the available free chlorine or bromine in your hot tub.

This is used when your sanitizer isn’t working as well as it should be. Shock is used when the sanitizer becomes overwhelmed after a large amount of debris is introduced into the hot tub.

Basically, shock is only used to boost your sanitizer’s effectiveness when it is not working as it should be.

Products such as soap, laundry detergent, makeup, cosmetics, deodorant, body lotions, body oils, shampoo, and conditioner that get into the water may cause the sanitizer to underperform.

What is the difference between chlorine and non-chlorine shock?

Chlorine shock will dissolve quickly, and has a neutral pH. It is excellent for restoring chlorine or bromine sanitizer levels. Non-chlorine shock works in much the same way but is not effective at algae or bacteria treatment. It can also result in cloudier water.

Many people are unsure of what they should use to clean their hot tub- chlorine shock or non-chlorine shock.  Chlorine granules come out cheaper ($6.55 a pound) by the pound than non-chlorine shock (MPS).

Chlorine shock sanitizes and oxidizes organic contaminants and diseases. It also has a lower price point. However, there is a strong chemical odor when chlorine is used.

MPS shock has low pH and also dissolves quickly.

It is an excellent oxidizer and a good sanitizer. Additionally, unlike chlorine shock, you can use your hot tub almost immediately after shocking it with non-chlorine shock.

You should wait at least twenty minutes before entering. There is no odor but it is a little more expensive than chlorine shock.

Shock can come in various forms, including liquid and powdered. Chlorine shock can come in granular form. Non-chlorine can come in a salt form. And of course, there is liquid chlorine.

You should shock your hot tub once a week. This ensures that bacteria are killed and your hot tub is sanitized. Shocking also removes organic compounds that are added to the water by anyone who bathes in it.

Multiple bathers and heavy usage can increase the number of organic compounds in your hot tub’s water.

Sometimes, however, we find ourselves having to add more and more chlorine or bromine, and yet the levels still never quite get to where they should be.

If you’re dealing with chlorine in your hot tub disappearing, read this recent article. I get into both why that happens, and the simple way to fix it.

Just click that link to read it on my site.

Do you need to shock a bromine spa?

Yes. A bromine spa still requires a weekly shock. Without shock, the bromine won’t be activated and will turn into bromamines which can give false readings on test strips and lead to unsafe water conditions.

For bromine to be effective, enough bromides need to be available.

Over time, and with each time you drain your spa or hot tub, your bromide count goes to zero. To build the level back up again you simply add granular (or liquid) sodium bromide.

Using shock activates the bromide, or converts it into hypobromous acid (HObr).

Once that has attacked a contaminant in the water, such as sunscreen, hair paste, dirt, bacteria, detergent, etc, most are reduced back to a bromide ion again.

Also, ensure you carefully measure your shock dosage. If you are even 1/2 an ounce off, either under or over, you can underdose or overdose your hot tub.

High chlorine levels can degrade surfaces quicker.

Water pillows, filters, and other surfaces can be negatively affected by high levels of chlorine in the water. Hot tub equipment can be negatively impacted by prolonged high chlorine or bromine levels. Pipes, the lining, and other equipment can degrade due to prolonged exposure to a large amount of chlorine or bromine.

In fact, too much chlorine or bromine can cause health issues such as red and itchy skin. High levels of chlorine and bromine are just as bad as an out of balance pH level.

Still unsure about the difference between bromine and chlorine?

Luckily, I break down all the pros and cons in a recent article. I get into cost differences, but also how they each affect your skin and nose. But, more importantly, which one lasts longer in the hot water, costing you less over time.

Just click that link to read it on my site.

Is Spa shock the same as chlorine?

Any brand of spa shock, unless clearly labeled as a non-chlorine shock, is will be chlorine-based. However, there are a number of different chlorine shock products on the market with different strength levels.

Shock is simply a high dosage of chlorine used to clear out unwanted bacteria, pathogens, and other contaminants.

Hot tub shock is an oxidizer. Oxidizers break down organic matter, ensuring clean water. You should shock your hot tub once a week. Shocking removes organic compounds that are added to the water by anyone who bathes in it.

Sodium dichlor is the most common type of chlorine-based hot tub shock. It is safe enough to add directly to the hot tub and does not need to be diluted first. 

Calcium Hypochlorite (Cal Hypo) is another type of chlorine-based shock often seen. However, this is more likely to be labeled for pools than hot tubs. Cal Hypo is much stronger than sodium dichlor. For that reason, it should be diluted in water before adding to a pool or hot tub.

Diluting it also helps prevent possible bleaching issues with the shell of your hot tub or pillows.

Cal Hypo is also really effective at eliminating algae. However, algae is usually much more of a problem in pools than in hot tubs.

Still confused about oxidizers, shock, and the differences?

Check out this recent article where I break it all down simply and easily. I even get into why you might want to use a non-chlorine shock to speed up how quickly you can soak after treating the water.

Just click that link to read it on my site.

Can you use pool shock in a spa?

Sodium dichlor is acceptable to use as a hot tub shock. Cal hypo is not usually recommended and must be diluted before adding to a hot tub. Technically most pool shocks are chlorine-based as are most hot tub shocks. The biggest difference is the strength of the chlorine.

So if all you can find is pool shock, that will work. Just start small, you can always add more if needed. And dilute if you’re using Cal Hypo.

But ultimately, a hot tub requires similar but different products to clean it. This is due to temperature difference and the amount of water in a hot tub as compared to a pool.

Typically, pool chemicals have different stabilizing ingredients.

For example, Cal Hypo has added calcium. If you already have hard water, that can make a bad thing worse. Cal Hypo is also not good for saltwater systems.

These ingredients aren’t the best for balancing hot tub water. They are geared towards pools. Additionally, these ingredients could alter your pH level to a point where your hot tub’s components are damaged.

So while they might do the job, it’s best to stick with products designed for hot tubs.

Did I cover all you wanted to know about whether you can use chlorine shock in a bromine spa?

A sanitizer is used to destroy disease-causing germs. When you sanitize water, it means you are removing bacteria from your hot tub.

Shock is used when the sanitizer becomes overwhelmed after a large amount of debris is introduced into the hot tub. This can happen after a party or a big storm.

Shocking a bromine hot tub helps activate the bromine and cleanse the water. Additionally, when looking at chlorine and non-chlorine shock, there are differences.

Chlorine shock will dissolve quickly, and has a neutral pH. It sanitizes and oxidizes organic contaminants and diseases.

Non-chlorine shock has a low pH. It also dissolves quickly. Additionally, you can use your hot tub almost immediately after shocking it with non-chlorine shock.


Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

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