What is Spa Shock? Why you need it and how to use it in your spa

An explanation of what spa shock is, why you should use it and how it works to help keep your water clean.

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What is the purpose of Spa Shock?

Shocking your spa will help break down waste and organic contaminants which cause odour and cloudy water. Once treated with spa shock, water quality and clarity are usually completely restored.

Shocking your spa can also remove irritating chloramines by converting them back to active chlorine if you are using chlorine sanitisers. Chloramines are a combination of ammonia with chlorine which can cause skin, eye and respiratory irritation in some people.

Spa shock can also kill bacteria and remove organic matter in your spa water.

How does Spa Shock Work?

Shocking a spa pool or swim spa is when you apply a dose of chlorine (sodium dichlor) or non-chlorine shock (potassium peroxy-monosulphate or MPS).

The ingredients in spa shock treatment react with organic waste material and contaminants in your spa water and help break them down quickly, so your sanitising product can then disinfect them.

Some people look at spa shock as a get-out-of-jail card to be used after a large bather load or if the spa water is not maintained correctly for a certain amount of time. Although not a fix-all, Spa Shock can bring spa water back to a higher level of clarity.

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What is the best spa shock treatment?

We recommend a chlorine-free spa shock treatment - such as our own Spa Store Spa Shock

Is Spa Shock the same as Chlorine?

Sodium dichlor shock is a form of chlorine and can act as both sanitiser and shock treatment. If you're using a chlorine-free shock product like MPS (potassium peroxy-monosulphate), then this will not have any chlorine in it.

Chlorine vs Non-Chlorine Spa Shock Treatment

Spa Shocks are compatible with most sanitising systems. We recommend a Chlorine-free (MPS) spa shock which works well with chlorine and chlorine-free sanitisers.

This non-Chlorine shock treatment is also compatible with Nature2 spa sticks and Simple Silver.

Can I add shock and chlorine at the same time?

No, you should not add shock and chlorine at the same time. The best thing to do is add spa shock treatment first and allow that to work, then test and add chlorine if needed.

What shock should I use with bromine?

We don't generally recommend bromine as a sanitiser product, however, if you are using bromine in your spa, you can use chlorine shock.

When should I use Spa Shock?

It is a good practice to shock once when you refill your spa. After that, regular maintenance shocking once per week is recommended.

Other times to use a shock treatment would include: prior to, or just after a party or other period of heavy bather load, when the spa has been neglected, or when restarting a spa that has not been used for some time.

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How do I use Spa Shock Treatment?

  1. It is best to apply shock to your spa in the morning or evening and when there are no bathers in the water.
  2. Remove your spa cover. This will allow the by-products of the reaction to be released into the air
  3. Wear appropriate safety equipment including gloves and safety glasses
  4. Balance your spa's pH and ensure it is between the recommended level of 7.2 and 7.6
  5. Start your spa pumps to allow water to circulate. (Leave your jets and air blowers off to reduce turbulence)
  6. Calculate the dosage based on the volume of your spa and the dosing instructions
  7. Carefully add the appropriate dosage to your spa. Don't apply on a windy day or with children present.
  8. Allow 15-45 minutes with the pumps running for the treatment to work before entering the water. (Check the directions on your shock).
  9. Check and Maintain pH in the range of 7.2 - 7.8, Total Alkalinity in the range of 150-200mg/L & Calcium Hardness in the range of 150-300mg/L

How long does Spa Shock take to work?

Most spa shock will work within about 15 minutes. No matter your method of shocking, make sure to remove your spa cover for at least 45 minutes after adding the shock to allow the shock treatment to work well. Every product is different so ensure you follow the instructions on the shock treatment product packaging.

How much Spa Shock should I use?

For the Initial Treatment use 30g per 1,000 Litres of Spa water. For Maintenance Treatment: 15g per 1,000 Litres of Spa water every week. Follow the directions on your specific shock treatment labels.

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Can I use Spa Shock with Purezone filters?

No. If you have a Vortex or O2 spa and you are using Purezone Micron filters you should not use an MPS spa shock. The MPS shock can react with the Purezone filter media and cause the Purezone micron filters to prematurely clog.

Instead of an MPS shock, you will want to use a higher dose of sanitiser as a shock. Please follow the dosing instructions on the label of your sanitiser.

Got more questions?

Contact us regarding your spa questions and we'll be happy to help!

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