How Does Shock Dosing Work?

Shocking your Lay-Z-Spa water refers to adding large quantities of chemicals (maybe 5-10 times the normal dose) in order to break down any organic waste and contamination and re-establish a positive level of sanitisation.

When Do I Need to Shock My Spa Water?

Your Lay-Z-Spa water should be shocked when:

  • You first fill up your Lay-Z-Spa
  • At the first signs of algae or slime
  • After periods of heavy usage
  • After a loss of water clarity or quality

How Often Should I Shock My Spa Water?

It is good practise to shock treat the spa water after a period of high usage. This will help to rectify the sanitizer level, prevent the growth of microorganisms and help maintain sparkling, crystal clear water. After treatment, water quality and clarity is often completely restored.
We know that chemicals are a pretty confusing part of owning a hot tub, so we have made it super easy for you with shock dosages depending on Lay-Z-Spa model and FAQs.

Lay-Z-Spa Clearwater Shock Dosing Rates:

Please note:
This guide is only applicable to Clearwater Chemicals. If you are using other chemicals, dosages may vary.
Dosages are only approximate depending on exact amount of water in your spa, water type, water temperature, positioning of spa etc.

Lay-Z-Spa Model

Water Volume (Litres)

"Commissioning" Chlorine Shock Dose
(40g per 1000 litres)

"Normal" Chlorine Shock Dose
(20g per 1000 litres)

Recommended Daily Chlorine Shock Dose

Palm Springs HydroJet





Hawaii HydroJet Pro




















Palm Springs










After shock treating your Lay-Z-Spa water, wait a minimum of 24hrs then test chlorine level. Bathing can start when chlorine level is 5ppm or less (ideal 3-5ppm).
One level teaspoon holds approx. 5g of dry product.

WARNING: You must always test your water before use. Water must be at recommended bathing level before bathing.

Shock Dosing FAQs

I purchased large 200g Chlorine Tablets for my Lay-Z-Spa. How many do I need to use?

These big tablets are designed for much larger swimming pools. Return them & exchange for Stabilised Chlorine Granules or small 20g Chlorine Tablets dosed with a floating dispenser OR Spa Chemical Starter Kit.
I purchased Small (20g) Chlorine Tablets for my Lay-Z-Spa. How many do I need to use?

It is difficult to give an exact dosing rate, but start with 2 – 3 tablets and adjust the flow rate to achieve chlorine level of 3-5mg/l (ppm) for spas.

I have added an initial dose of Stabilised Chlorine to my spa, when can I use it?

The spa can be used when the chlorine level has dropped to 5mg/l (ppm) or below. This may take some time.

I have added an initial dose of Stabilised Chlorine to my spa. I am getting strange pH & Total Alkalinity readings?

The chlorine level is still probably very high which can give inaccurate pH & TA readings. Wait for the chlorine level to drop to 5mg/l (ppm), then re-test pH & TA and if necessary adjust.
There isn’t a measuring scoop in the chemical container. How do I measure out the quantity I need?

A level teaspoon holds approx. 5g of dry product. Never use the same teaspoon to measure different chemicals without
cleaning thoroughly first.
How often do I need to add Stabilised Chlorine Granules to my spa?

The Stabilised Chlorine Granules should be added daily to achieve the recommended chlorine level of 3-5mg/l (ppm) for spas.

I have purchased a starter kit for my Lazy Spa, when do I add the algaecide?

You have purchased a Pool Starter Kit rather than a Spa Starter Kit. You do not need to add algaecide to a spa.

I need to buy more chemicals, where can I purchase them from?

You can purchase further hot tub chemical supplies from the website.
Why am I not getting a chlorine reading on my test strips?

Have you added any chlorine recently?
Yes, an initial dose for my spa – The chlorine level may still be high leading to bleaching of the test strip pads. Leave for 24 hours and re-test.
No, I added chlorine a couple of days ago. Chlorine gets used even if the pool/spa isn’t being used. Dose Stabilised Chlorine Granules daily.