How to Shock Your Hot Tub, and When to Do It
Shock your hot tub once a week, and after a busy session
Shock treatment lifts the water between sanitiser doses, so it stays fresh and clear. This guide covers when to shock, how much non-chlorine shock to add for your water, and how to add it safely.
Wait at least 20 minutes before you bathe, with the cover off.
When to shock
The CDC advises a shock treatment daily to weekly, depending on how the tub is used.1
For most tubs, once a week is a simple default. Shock more often after a busy session or a heavy weekend, or when the water has odours or feels oily from lotions and body oils. Our non-chlorine shock is labelled for those jobs.2
How to shock your hot tub
Shock with the pumps running and the cover off, so the treatment spreads evenly and oxygen can reach the water.2
Check pH first
The label asks for pH between 7.2 and 7.6 with a chlorine sanitiser, or 7.0 to 7.4 with bromine. Keep your sanitiser at the levels in our sanitiser guide.2
Take the cover off
Oxygen needs to reach the water, so keep the cover off while the shock works.2
Dissolve the granules
Dissolve the granules in clean water, using the dose on the pack, until they have fully dissolved.2
Pour with the pump on
Pour the solution into the water near the inlets with the pump running, so it circulates evenly.2
Wait before bathing
Wait at least 20 minutes before you bathe, and keep the cover off for that time.2
How much to use
The dose depends on the volume of water in the tub. The label gives these amounts for the non-chlorine shock.2
| Water in the tub | Dose of non-chlorine shock |
|---|---|
| 1,000 litres | 11 g |
| 2,000 litres | 22 g |
| 4,545 litres | 50 g |
The product
Hot Tub Non Chlorine Shock Granules, 1 kg, are in stock now. This is the shock this guide is written around.
Hot Tub Non Chlorine Shock Granules
1 kg · £16.99
Chlorine-free shock granules that lift the water between sanitiser doses. Follow the label for dosing.
Quick answers
Open a question to read the answer.
How often should I shock my hot tub?
The CDC advises a shock treatment daily to weekly, depending on use. Once a week is a simple default, and shock after a busy session.
Can I get in straight after shocking?
Wait at least 20 minutes before you bathe, with the cover off.
Does shock replace my sanitiser?
No. Shock works alongside your main sanitiser, so keep that at the levels in the sanitiser guide.
Can shock help cloudy water?
Yes. The product page says it helps restore cloudy water and makes it clear.
Sources
- Centers for Disease Control and Prevention, Operating and Managing Public Pools, Hot Tubs and Splash Pads (dated 10 January 2025): pH 7.0 to 7.8, testing at least twice a day, shock daily to weekly
- Outdoor Living, Hot Tub Non Chlorine Shock Granules product page: dose, pH, wait time and use (current)
Paul Margerison
Managing Director & Founder, Outdoor Living
Clear water is a routine, not a one-off job. A weekly shock is one of the simplest habits that keeps it that way.