How Much Bleach To Shock Hot Tub?

By Adam


When it comes to shocking a hot tub, there is an art to it. It is a procedure that needs to be done carefully and safely, as do all processes involving bleach. 

We want to do the right thing and ensure that our hot tubs are clean and safe spaces, but bleach can be a daunting substance to use.

After all, no-one wants to be sitting in a hot tub filled with smelly chemicals that itch their skin, do they?

But fear not, today we are here to tell you how much bleach to shock hot tub is needed and talk you through the process! Just sit back, relax, and before you know it, you will be shocking your hot tub!

What is shocking?

Before we go any further, let’s look at what we mean by shocking a hot tub.

Shocking a hot tub involves adding a higher than normal amount of a chemical, bleach, chlorine, or bromine, for example, to the hot tub. It is sometimes referred to as oxidizing. 

Shocking a hot tub will control any bacteria growth in the tub, sanitizing the water. It also removes any organic contaminants that enter the water when multiple people use the hot tub, such as a family or a group of friends.

If you have had a party and lots of people have used the hot tub, sometimes the contaminants’ levels can be higher than your usual cleaner can manage. 

Shocking is recommended by some brands weekly. It is always worth checking with the manufacturer before shocking to meet your hot tub’s needs fully. 

What is the difference between bleach and chlorine?

When it comes to cleaning a hot tub, we see bleach and chlorine often interchangeably. So before we get into the amount you should be using, let’s clear this up. 

Chlorine and household bleach are the same thing, but chlorine is at least three times stronger than any household bleach on the market.

It is generally recommended that chlorine is used instead of household bleach to shock your hot tub as it ensures a deep clean and removal of bacterial growth in the hot tub. 


Chlorine is a substance we have to handle carefully, avoiding contact with our skin, mouth, and eyes, and kept safely away from children and pets.

Usually, when we see the word ‘bleach’ concerning hot tubs, they will mean chlorine.

If you see the phrase, ‘household bleach,’ that will refer to the liquid bleach bought at a supermarket, which is used for cleaning your home, bathroom, drains, etc. 

How much chlorine should I use?

Now that the distinctions have been made let’s get into it! Chlorine levels are measured in ppm, parts per million, and should be measured in relation to the size of your hot tub. 

Some hot tub instruction manuals will have instructions on how best to do this, but typically it can be anywhere from 5-10 times the usual dose of chlorine used in your hot tub. 

You can purchase a specific spa shocking chlorine, which will tell you on the label how much chlorine to add to your hot tub, depending on the size. These are an excellent option to go for; why not try one of the bestsellers?

You must get the dosage right to ensure that you shock your hot tub; if you are out by as little as half an ounce, it won’t work correctly. 

How much bleach should I use?

Using regular household bleach to shock a hot tub can be done. It is best to use a bleach that is unscented and free from additives, be sure to check the label before purchasing! 

The amount of bleach will depend on your hot tub; you can work this out by using a chlorine testing kit. For example, for a 300-gallon spa, 8oz of household bleach would shock the hot tub. 

It’s important to remember that using household bleach can dramatically raise your hot tub’s pH level, and using chlorine is the better option. 

Factors to consider

Before you dash off to shock your hot tub, there are some factors to consider first. Making sure you have the right amount of chlorine is the most critical factor.

You can find this information on the chlorine bottle, instructions, or often the manufacturer of the hot tub will have advice about this. 

When it comes to shocking your hot tub, the chemicals you are using and the chemicals already in your hot tub are essential to consider.

Mixing chemicals is hazardous; it can cause dangerous reactions in the water and air.

When mixed with other chemicals, Chlorine can create a harmful gas in the air, so be sure to only use it in hot tubs that have previously been cleaned with chlorine. 

Those who have used other chemicals will need to drain and refill the hot tub before adding chlorine to the water. 

It is also wise to ensure that you wear protective clothing when using chlorine to shock your hot tub. Keeping your arms covered, wearing gloves, and possibly protective eyewear is a good idea.

Even the slightest change in the wind could cause the chlorine to splash onto your skin. 

It is also crucial that you carefully follow the steps on how to shock your hot tub. This information can be found on the chlorine bottle, in a hot tub manual, or directly with your hot tub manufacturer. 

Final word

As you can see, when it comes to shocking your hot tub, no one answer fits all.

The amount of chlorine needed to shock your hot tub will depend on the size of your hot tub and pH level to accurately kill the bacteria and ensure a clean and safe hot tub. 

Although you can use household bleach to shock your hot tub, you will be left with a too high pH level. Chlorine is the better option to use.  

Be sure to check the dosage carefully before use and follow the steps to shock your hot tub to ensure you are left with a clean and happy hot tub to enjoy once more!