Should I use chlorine or non-chlorine shock in my spa?

Should I use chlorine or non-chlorine shock in my spa?

If your hot tub water starts looking dull, cloudy, or just not as fresh as it should, you might wonder which shock treatment is the right one to use. Both options can clean up your water, but they work differently, and knowing when to use each one makes spa care a lot easier.

What Chlorine Shock Does (and When to Use It)

Chlorine shock is the stronger, more aggressive option. It’s designed to kill bacteria, algae, and contaminants quickly, which makes it ideal when your water feels “off” or has that unpleasant smell.

You might choose chlorine shock if:

  • The water has gone cloudy

  • The spa smells musty or overly chemical

  • You’ve had heavy usage (like a party or long soaking session)

  • Your sanitizer level has dropped too low

Chlorine shock resets the water but also raises chlorine levels for a few hours, so you’ll usually need to wait before hopping back in.

Think of chlorine shock as your deep-clean option.

What Non-Chlorine Shock Does (and When to Use It)

Non-chlorine shock (often potassium monopersulfate) works as an oxidizer rather than a sanitizer. It breaks down oils, lotions, sweat, and organic waste that builds up in spas. This keeps your sanitizer from getting overwhelmed.

You’ll want to use non-chlorine shock when:

  • The water looks a little dull but not dirty

  • You want to freshen the water without adding more chlorine

  • You prefer soaking sooner, usually within 30–60 minutes

It doesn’t kill bacteria, but it does help your sanitizer work better. For bromine users, it’s especially helpful because it reactivates bromine without affecting balance.

Can You Use Both Types?

Yes, you can switch between them depending on what your spa needs.

  • Use non-chlorine shock weekly for regular maintenance.

  • Use chlorine shock as needed for problem-solving or full resets.

If you're using chlorine as your sanitizer, either type works. If you’re using bromine, non-chlorine shock is generally the better, more compatible choice.

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