How do I shock my top hot tub?

Posted by Nick Clamp in Maintaining a Hot Tub Guides on 8th February 2021

Before you become an owner of a top quality hot tub from a respected WhatSpa? Approved dealer you may be alarmed to discover that you will have to ‘shock it’ on a regular basis. There is no need to worry, though, as this chemical dosing process is one of the effective ways to guarantee that your hot tub water is free from contamination and safe for a soothing soak. This treatment process should never be viewed as a hassle or major chore, as it must be conducted as part of a hot tub water maintenance and a responsible duty of care routine.

Why should I shock my hot tub?

Photo © Hot Tubs Hampshire

To prevent oils and contaminants building up shock treatment ensures you gain the best possible use of your hot tub with clean water benefits and the peace of mind that it is safe.

The last thing you want is nasty hot tub bacterial growth, but by recharging your sanitiser with a shock treatment it will ensure you benefit from ‘showroom quality’ hot tub water.

If you suspect that your hot tub water quality is deteriorating then a shock treatment may be necessary. It is much better to act responsibly than to be faced with murky or contaminated water when all you want to do is relax and enjoy top quality hydrotherapy.

Shock compounds explained

Chlorine-based shock treatments and non-chlorine-based shock treatments are the two main shock compounds. 

Chlorine shock treatments

Chlorine-based shock treatments will combine oxidizers and disinfectants but can tend to be harsher treatments for your water, and could cause corrosion issues, so that it may be the case that they are used periodically.  They are most preferable when you are conducting a complete water change or as part of a comprehensive hot tub cleaning process to ensure the recommended tip top condition for safe operation.

Non-chlorine shock treatments

Non-chlorine shock treatments, on the other hand, can be used more regularly, on a weekly basis for example, as this process can maintain your clean water, but be aware this process will not disinfect it.

Also consider bromine

To gain the disinfection qualities of chlorine you may also consider using bromine, which has the advantage for hot tub use of being stable, insensitive to pH variations, UV, and high temperatures. Another advantage of bromine is that it has less odour than chlorine and will not create additional by-products like chlorine does, such as chloramines.  It should be noted, though, that bromine treatments should not be combined with chlorine as they are incompatible products.

How to shock you hot tub step-by-step guide

As a general routine the shock treatment process should be part of a responsible owner’s water maintenance process. It is best practice to become proficient in the shock process to ensure it is an easy routine that you can always be capable of getting to grips with and performing yourself. 

  1. First you will need to adjust your pH levels of your hot tub water to between 7.4 and 7,6 and have the cover off to perform the shock so your hot tub is ‘open’.
  2. Then, while the circulation pump is running, you should turn off the air to the jets to ensure that your hot tub water has movement without the extreme force of the jets. It is also a good tip to ensure children and pets are out of the way and that you have rubber gloves and goggles ready at hand for when you are applying the shock.
  3. Now comes one of the preparation and application processes that is not to be rushed. After consulting your shock treatment instructions, you will need to measure out the correct level of shock treatment to correspond with the water total that is currently in your hot tub.
  4. Once you have the correct level of shock you should apply it to the water, using gloves and goggles to avoid risk to your hands and eyes from the chemicals,  with utmost care. Naturally, if any of the shock treatment is dropped on the surface or exterior of the hot tub or on the ground then you should make every effort to clear it up immediately.

How long do I wait to us the hot tub again?

Never rush to immediately jump in your hot tub without first completing a post-shock test, as there is the problem of not knowing if the chlorine levels have reduced sufficiently for safe hot tub use. 

Consult your shock treatment instructions to follow advice on how long you should wait to utilise your hot tub after administering shock treatment, but, generally, times can be between 20 minutes and an hour. On other occasions you may have to delay your soak time much longer, by up to 12 hours or even a full day.

If you have a ‘spa-rty’ date planned then it is always the best policy to plan well ahead and get your shock treatment purchased in advance to avoid any disappointing delays or unfortunate cancellations.

Testing your hot tub water after a shock should always be part of your dedicated process and if the chlorine levels have dropped below 5ppm then you will be good for solo or group soaks.

How often should I shock my hot tub?

Photo © Villeroy & Boch

Ideally you should be shocking your hot tub every week. However, consistent levels of high volume use and even not using hot tubs on a regular basis will necessitate varying shock treatment application requirements for clean water.

If you are going to be engaging in large hot tub gatherings in quick succession during a short space of time, this may create the need for multiple shock treatments during the week.  It may also be the case that you are going on holiday for a few weeks or have not been using your hot tub for a while, which will then require a pre-soak shock.


Owning and utilising a hot tub on a regular basis has its many health benefits but these, critically, must always be gained with essential water maintenance care and recommended testing routines for maximum safety. As a responsible hot tub owner, you should always be checking your water before use to ensure it is safe and take advantage of the recommended shock treatments as part of this process. If you are ever in any doubt about water maintenance requirements for your hot tub, or other operational processes, then you should consult your supplier or a professional fully qualitied hot tub technician.

About the author

Nick Clamp

I am the Editor-in-Chief at WhatSpa? Media Group and my job is to keep you informed about the very latest hot tubs on the UK market... the best job in the world! When I'm not being deluged with press releases and hot tub brochures I enjoy keeping fit and participating in endurance events including triathlons and distance running.

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