How To Shock A Hot Tub


Does the water in your hot tub smell funny? Is it cloudy? Then it’s about time you gave your tub a shock dose!

But hey, we are not saying that you should dress up like a clown, holding a bunch of balloons and go chasing after it, absolutely not! Heck yes, this is quite terrifying but it is definitely not the kind of “shock” we are talking about. A hot tub shock is more of ensuring the water in it is clean, healthy, and comfortable to soak in.

Nobody wants to bathe in a dirty, unkempt tub, so to make sure that this never happens, always shock your water to keep it free from contaminants. Whether you have had your spa used frequently or haven’t soaked in it for months, it is important to shock it before immersing yourself in the water.

In today’s article, we are going to give you tips on how to shock a hot tub effectively without detrimental side effects. Whether you own a permanent or inflatable hot tub, these pointers are going to ensure a healthy soak. So grab your lab coat as this is going to be one hell of a chemistry lesson!

But first…

What Is Shocking A Hot Tub?

This is adding an oxidizer chemical to your hot tub water in a higher dose than usual to destroy bather impurities and control bacteria growth. The process is also known as oxidizing.

When you add an oxidizing agent to your hot tub, the pathogens and contaminants in the water lose electrons and cease to exist. Sounds complicated? Okay, let’s break it down!

When the oxidizer comes into contact with the contaminants, it steals their out electrons making them weak and vulnerable to attacks. Their cells are destroyed, which eventually destroys their molecules, leading to their death.

Why It Is Important To Shock Your Hot Tub

The main reason why many people shock their spa is to keep the water clean and safe for soaking. Others do it to remove the cloudiness in the water. But here is exactly what adding an oxidizer to your hot tub does for the water:

1. Gets Rid Of Organic Compounds

Do you use your hot tub frequently? Do you allow two or more people to use the spa at once? Then shocking your tub is the first thing you need to do the next time you go for a soak.

If your spa is used quite often or you have had several people going in there in one go, the organic compounds in the water can increase. To make sure the tub is clean for the next soak, you will need to remove these compounds.

2. Kills Disease-Causing Bacteria

Shock compounds made from bromine and chlorine can be used to destroy and kill bacteria that breed in your water to make it healthy and safe to use. Maybe you sanitize your spa regularly, but sometimes, especially when the tub has been used by several bathers, it can be difficult to contain the pathogens with the normal disinfecting routine.

3. Removes Chloramines And Bromamines

The contaminants in your hot tub can form chloramine and bromine bonds that cannot be broken using the normal sanitizers. A shock breaks these bonds so that you can easily remove them from the water.

4. Gets Bromides Back To Action

If you use bromine in your hot tub, adding an oxidizer once a week reactivates the bromine ions and converts them into hypobromous acid, a killer compound that destroys bacteria and pathogens. This keeps your spa clean and safe to use.

When To Shock Your Hot Tub

You should always shock your spa:

  • The first time you set your hot tub and fill it with water and every time you do a refill
  • The minute you start seeing signs of slime or algae
  • If the water is smelly, looks cloudy, or has turned into some funny color
  • If the water is foaming
  • If you or someone else has accidentally peed in the spa
  • If you have had a few friends use your tub at once
  • If you have been using the tub quite often

However, sometimes you will find that none of the things mentioned above apply and may think that shocking your spa is not important. But even if this is the case, you should add shock to your tub at least three times a month or even twice a week if you are a heavy user. This will destroy any invisible nasties and keep your water hygienic and sparkling clean.

What Shock Compound Should You Use On Your Spa?

The two main shock compounds available in the market today are chlorine and non-chlorine. Each has its own benefits over the other but would play an important role in ensuring a clean spa. Even pool owners can use these during their pool maintenance to ensure a healthy swim area. Let’s dig a little bit into each of these compounds:

Chlorine Based Shock

A shock made of chlorine can be both an oxidizer and disinfectant. Use this when you open your tub for the first time or whenever you have the water changed. A chlorine shock can also be the best hot tub shock for your spa if you have been using it regularly or have had multiple users. However, experts advise that the usage of chlorine shock be minimized because the chemicals can be really hostile toward your plumbing and may end up corroding it.

When you add a chlorine shock into your tub, it raises the chlorine levels of the water, which means you would have to wait for a while for these to go down naturally before having a soak. You will also need to remove the cover of the tub and leave it open for about 15 minutes to allow air to circulate in your tub. This prevents chemicals from damaging the cover of your tub.

Non-Chlorine Shock

A non-chlorine shock is not a disinfectant and will not kill pathogens in your tub, so if this is what you want to get rid of, then you might want to consider a chlorine shock. Non-chlorine shocks however make the perfect oxidizers. They oxidize the contaminants and clean up the water in your spa.

Non-chlorine shocks can be used regularly depending on how often you use your tub. Those on bromine can also use this product to help the bromine work more efficiently.

Shocking A Hot Tub


Shocking a hot tub is an easy process and one doesn’t need to be a genius to carry it out. You don’t even need to ask for help from an expert. Just add the shock into the water, sit back and watch it do what it does best. Here is how you go about it:

Check The PH Value Of The Water

Even before you add the shock to your spa, you need to determine the acidity and alkalinity of the water by carrying out a PH test. Again, this is not rocket science and you don’t even need to know chemistry to do this. All you got to do is:

  • Get a hot tub test kit (this is color-coded and will cost just a few bucks)
  • Get a strip from it and dip it into the water of your spa and wait for about 15 to 20 seconds
  • Hold the strip against the color chart provided to determine the PH value of your water
  • If your water has the right PH levels, you can go ahead and add the shock. Otherwise, you will need to adjust it until it gets to the correct values before shocking the spa. The recommended PH levels should be between 7.4 and 7.6.

Shock Your Spa

Chlorine shocks destroy contaminants powerfully and quickly. The only downside is that they emit a strong scent when the reaction starts to take place. The smell is just so unpleasant that sometimes it can even irritate your nose or eyes. To shock your spa with chlorine:

  • Remove the cover of your hot tub so that it can aerate while being dosed
  • Get a bucket and fill it with water from the tub
  • Make sure the air to the jets is turned off and the circulation pump is running
  • Using the instructions given on the label of your product, measure the number of chlorine granules you need depending on the number of water gallons your spa holds
  • Add these granules to the bucket and stir to dissolve
  • Pour the dissolved chlorine into the spa and turn the air bubble jets on. If you are doing this in an open, and especially in a wind prone area, you need to be very careful as the chemicals could get blown right into your eyes.
  • Leave the tub for about 20 minutes to allow the gases emitted to escape into the air
  • Cover the spa and leave it overnight. If you are shocking your tub during the day, you can leave it for several hours
  • Test the water’s chlorine levels to ensure that it is in the right range. The acceptable range is 1-3ppm.
  • Your tub is now safe to use!

A non-chlorine shock can be used as an alternative to chlorine. For starters, its smell is not as strong as the chlorine-based shocks, and second, it is not harsh on the skin. The only disadvantage is that you will need to shock your tub more often and keep a keen eye on the PH levels of your water than when using chlorine shocks.

How Soon Can You Use Your Spa After A Shock?

There isn’t a specific period of time that is set for when one should or should not use a hot tub aftershock. Nevertheless, the water must be tested to make sure that the chlorine levels are back to normal before having a soak.

Some hot tubs will be safe to use after 20 minutes while others will take even 24 hours for the conditions to normalize. Most of the time this information is written on the label, so check this to see when is the best and safest time to dip yourself into the water. The time is taken for chlorine to get to the safe levels, however, largely depends on the number of granules used to shock the tub.

Spa Chemical Safety

All chemicals are dangerous and that is one of the reasons why all of them come with instructions on what to do and what not to do to stay out of harm. A hot tub shock, being one of these is no exception and it is always important to consider the following tips before, when, and after handling it:

  • Read the label of your chemical product before use and be keen to follow all the instructions stated
  • Never mix chemicals yourself unless it is stated on the label
  • Add chemicals to water, not water to chemicals
  • Never add a shock to a hot tub that is in use
  • Mix chemicals in an area that is well ventilated and avoid windy spots when dealing with powdered chemicals
  • Keep hot tub chemicals in areas where children and animals can’t reach
  • Wash your hand thoroughly after touching spa chemicals
  • Always wear protective clothing when dealing with strong chemicals
  • If you spill hot tub chemicals accidentally, make sure to clean the spot with plenty of water
  • Store your chemicals away from moisture and direct sunlight

Globo Surf Overview

There you go – every single thing you need to know about shocking your hot tub. As you can see, the process is pretty easy so you have no reason not to give your spa a shock dose.

You really don’t want to soak in a dirty or cloudy hot tub after a long day at work. Maybe you clean your spa daily but sometimes, this is just not enough. You need to perform a thorough hot tub shock to ensure the water is clean and safe to use. Also, make sure to take the necessary safety precautions when handling hot tub chemicals to stay out of harm.

More Hot Tub Reviews:


  1. How Often Should You Shock A Hot Tub?
  2. How To Apply Chlorine Shock To Your Hot Tub,
Globo Surf
My name is David Hamburg. I am an avid water sports fan who enjoys paddle boarding, surfing, scuba diving, and kite surfing. Anything with a board or chance I can get in the water I love! I am such a big fan I decided to start this website to review all my favorite products and some others. Hope you enjoy!