How to Shock a Hot Tub

Hot tub carred by Zagers Pool & Spa

A hot tub adds a touch of warmth and relaxation to the end of your day, invites friends to soak and laugh with you, and it’s a great place for your family to reconnect when life is busy. At Zagers, we understand the important role a hot tub or spa can play in your family’s life. Here are our tips on how – and why – to shock your hot tub so the water will be clean and sanitary whenever you’re ready to use it.

Why Should I Shock My Hot Tub?

Cloudy water and hot tub scum don’t help create great memories, so you want to use hot tub shock regularly! It has three primary functions to keep your water clean and sanitized:

1. It eliminates organic contaminants. You know those signs next to public hot tubs that ask patrons to shower before entering? They’re there for good reason. Showering can help remove things like shampoo residue, lotion, make up, and even dead skin cells that come off when you’re soaking. But showering doesn’t remove them entirely. Think about how many people are using your hot tub—and all of those contaminants floating about in your water. Yuk!

2. It eradicates chloramines and bromamines. Whether you use chlorine or bromine as your sanitizer, the waste product they produce (chloramines and bromamines, respectively), can be bothersome to breath in. Hot tub shock helps return your sanitizer to the proper level, breaking the bond the sanitizer forms with the contaminates it’s destroying. The contaminants can then be filtered and the sanitizer is free to continue killing bacteria. Pretty cool!

3. It kills unpleasant illness-causing bacteria, like pseudomonas aeruginosa, legionella, and non-tuberculous mycobacteria, as well as algae, viruses and pathogens—all stuff you don’t want lurking in your hot tub.

Can I Shock a Hot Tub with Bleach?

Now that you understand why you want to shock your hot tub (so many reasons!), let’s talk about how you can do so. One way is to use regular household bleach, although that is NOT Zagers’ recommendation. If you choose this method, be sure to use a bleach that’s unscented and doesn’t have additives. Bleach can cause the pH level to rise so you’ll have to test the water carefully. We highly recommend using one of the other two methods for more pH-neutral options.

Should I Shock a Hot Tub with Chlorine?

Probably the most effective way to shock your hot tub is by using chlorine granules, which are sold in varying concentrations, or liquid chlorine, depending on your sanitization system. (Check with your hot tub manufacturer, if you’re not sure which is best). Using a chlorine-based hot tub shock, like Dichlor shock or Spaguard Enhanced Shock by Bioguard, will tackle all three of the issues we outlined above.

What About Shocking with Non-Chlorine Shock?

Non-chlorine shock does a great job of removing those nasty organic contaminants from your hot tub, but it doesn’t kill bacteria. You read that right—it does not kill bacteria. 

However, non-chlorine shock dissolves quickly and is an effective oxidizer. That means that it helps break the bonds that chlorine forms with contaminates, so that the free chlorine can be active and work on killing bacteria. It also helps reactivate bromide ions, turning them into active, more effective bromine. Bottom line: a non-chlorine shock, like Spaguard Spa Shock-Oxidizer by Bioguard, can be used between regular chlorine shocks to help keep your hot tub water clear and free from scum.

Don’t Shock a Hot tub with Bromine or Calcium Hypochlorite

Bromine ions (which are sometimes confused with a hot tub shock) are not a bromine shock—there’s no such thing.

Calcium Hypochlorite, also called cal hypo, is unstabilized chlorine that’s designed for use in a pool. It’s not effective in a hot tub.

How to Shock Your Hot Tub

Now that you understand the different components, the next part is shockingly easy.

When you’re ready to shock your hot tub, you’ll need to completely uncover it, test the pH (you want it to be between 7.4 – 7.6), and leave your pump on but turn your blower off. Also be sure to wear safety gear!

Measure the shock, add it to your hot tub, and leave your cover off for at least 20 minutes.

A Few Final Tips

  • If your hot tub is indoors, you can shock it anytime. If it’s outside, we recommend waiting until dusk or nightfall, unless it’s covered by a structure, like a patio.
  • Always test your hot tub water before getting back in.
  • Be sure to store shock out of the reach of pets and children.

If you have questions or would like more information on shocking your hot tub, contact us. We’d love to teach you how to properly shock your hot tub so you can create those wonderful memories.

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