How to Shock a Hot Tub or Spa

How to Shock a Hot Tub or Spa

If the phrase 'shock dosing your hot tub' has made waves in your conversations and left you puzzled, fear not. This article is your comprehensive guide to decoding the concept of shocking a hot tub or spa. We'll dispel common myths, explore why routine shock treatments are crucial, explore the diverse chemicals at your disposal, and discuss the most secure methods to implement this procedure. So, without further ado, let's dive deep into the world of hot tub shock treatments! 

What is a Hot Tub Shock Treatment? 

Shocking a hot tub or spa means introducing a higher dose than usual of oxidizer chemicals into the water – also known as oxidizing. It's advisable to perform this process once a week to diminish bacteria and impurities. You can use either chlorine shock or non-chlorine shock products for this purpose. 

Why Shock Your Hot Tub? 

The primary objective of shocking your hot tub is to maintain clean and clear water. In addition to this, shocking your spa helps in: 

  • Killing Bacteria: Chlorine-based shock treatments effectively sanitize hot tub water, keeping it safe for users. 
  • Removing Organic Contaminants: Standard sanitizers can struggle to manage waterborne organic compounds, especially in high-usage scenarios. However, shocking effectively eliminates these pollutants. 
  • Reactivating Sanitizers: Sanitizers such as bromine or chlorine bind themselves to contaminants, becoming 'used' in the process. Shock treatments break this bond and separate the chlorine particle from the pollutant, leaving it in the filter. This reactivates the chlorine, enabling it to continue killing bacteria. 

Which Type of Shock Should You Use? 

While chlorine and non-chlorine shock treatments have benefits and drawbacks, combining both methods is advisable, provided your water type and bathing routine allow this. 

Chlorine Shock: This treatment is an excellent disinfectant after heavy use or a water change. Remember, though, that chlorine shock increases the chlorine level in your hot tub. You'll need to wait for it to naturally decrease before using your spa. During this waiting period, leave the cover off for at least 20 minutes while running a regular jet cycle to prevent chemical damage to the tub and accessories. 

Non-Chlorine Shock: This type of shock doesn't disinfect the water but is used primarily as a weekly treatment to oxidize, remove contaminants, and clear cloudy water. It also helps chlorine work more efficiently to eliminate bacteria. 

Note: If you use a bromine sanitizer, both chlorine and non-chlorine-based shock treatments are suitable. However, never mix the dry chemicals directly, as it can cause a dangerous chemical reaction. 

How to Shock Your Hot Tub 

Shocking your hot tub's water is relatively straightforward once you know the volume of your hot tub. Follow this step-by-step guide for the best results: 

  1. Remove the hot tub cover to let oxygen reach the water's surface. 
  2. Ensure the pH balance is correct – between 7.2 and 7.6 with a chlorine sanitizer or 7.0 to 7.4 with a bromine sanitizer. 
  3. Turn on the jets to aerate the water (avoid switching on the blower if you have one). 
  4. Read the label on your chosen chemical. Most products recommend 17g of non-chlorine shock or 35g of chlorine shock per 1,500 liters of water. 
  5. Carefully pour the treatment into the spa near the water inlets for even circulation. 
  6. Wait for at least 20 minutes before using your spa, keeping the cover off during this time. 

How Long Should You Wait After Shocking? 

The wait time before using your hot tub varies among brands and can range from 20 minutes to 24 hours. Using a test strip to ensure that your chlorine levels are safe before getting in is always a good idea. 

Pro Tip: Non-chlorine shock treatments don't sanitize the water, meaning you can usually use your hot tub around 20 minutes after adding the chemical. 

Hot Tub Chemical Safety 

Following these tips can help you handle hot tub chemicals like a pro: 

  • Always read the product label and follow its instructions before use. 
  • Never mix hot tub chemicals unless advised to do so by a specialist. 
  • Always add chemicals to water, not the other way around. 
  • Never add chemicals to your hot tub water while it's in use. 
  • Use hot tub chemicals in well-ventilated areas. 
  • Be cautious of strong winds when using powdered chemicals. 
  • Store chemicals out of the reach of children and animals. 
  • Wear protective shoes and clothing when handling chemicals. 
  • Wash your hands thoroughly after use. 
  • Test your hot tub water daily with test strips. 
  • Store all chemicals away from heat and moisture. 
  • Always leave your hot tub switched on unless you change the filter or water. 


While shocking your hot tub might initially seem daunting, a clear understanding of the process can make it simple and manageable. It's an essential aspect of hot tub maintenance, helping you maintain a clean, safe, and relaxing environment. Remember, safety comes first! Happy soaking!