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How to Shock a Hot Tub

Hot tub shocking is simply the process of adding a large dose of sanitizer at once. We shock hot tubs to kill contaminants and re-balance sanitation levels. Think of it as a water 'deep-clean' between routine sanitizer top ups and water changes.
hot tub shock

How often Should I Shock My Hot Tub?

How frequently you shock your hot tub should depend on usage level, but you should also shock your hot tub:

• On first start
• After heavy use (e.g parties or full capacity)
• After a water change
• If water starts to become regularly cloudy or murky
• Periods of hot tub inactivity (family holidays, cold weather etc.)

Types of Shock

There are two types of shock which can be added to water: chlorine shock and non chlorine shock. It's important to understand the difference between chlorine shock and non chlorine shock as each type performs a different role.

Chlorine Shock

Chlorine Shock can be used in chlorine treated tubs as well as bromine and salt water tubs. Chlorine shock can also be used in hot tubs where a UV sanitization system or ionizer system is used. However, not all hot tub manufacturers recommend the use of chlorine shock with these systems so be sure to check the manufacturer guidance before using.

Non Chlorine Shock

Non chlorine shock is not a disinfectant but rather an oxidising agent. Oxidising agents work to break down contaminants in the hot tub water into smaller particles which can be drawn out through the filter. It is recommended most hot tub owners use an oxidising agent once a week.

How to Shock a Hot Tub

Shocking a hot tub is an easy, straightforward process and it only takes a couple of minutes to complete.

Step One:

• Check water level

Before shocking your hot tub you will need to ensure the hot tub's water level is filled to the recommended capacity. At combined shipping, you will see each of our hot tubs are fitted with a 'fill line' sticker which is located on the inside of the shell. it is important that the water is filled to this line as chemical doses are recommended based on water capacity.
hot tub fill line
Step Two:
•Check water PH

Using a hot tub test strip, you will need to take a reading of the waters PH. A properly balanced PH level will ensure the shock can do its job properly. If the PH is out of balance, the shock treatment may not work.

Step Three:

•Balance PH

Balancing your hot tubs PH may sound very scientific, however the process is simple. To balance your PH all you will need is a PH plus or PH minus solution, both of which can be purchased from most hot tub retailers, including Combined Shipping hot tubs. If you do find your PH is out of balance, this can easily be rectified with a PH plus or minus solution. Ideal water PH is somewhere between 7.4 and 7.6 but determining the exact PH isnt necessary. The test strip will indicate the PH level by colour, which can be compared to a colour chart on the bottle.

Step Four:

•Add the Shock

Add the shock to your hot tub according to shock manufacturer instructions. If you are adding shock before first use, this is known as a commissioning shock dose and more shock will be required. If you are shocking your hot tub after first use then this is known as a normal chlorine shock dose.

On the shock container, you should find instructions on exactly how much shock to add in accordance to your hot tubs capacity. If you are adding the shock to cold water (below 20°C) you will need to pre mix the solution in a container with a small amount of warm water first. This will allow the solution to dissolve properly. When adding the chlorine shock, ensure your spa is turned on and the pumps are functioning. This will allow the shock to circulate properly throughout the system. It is also advisable to add the shock next to the water inlets (typically found on the bottom of your spa). Take care not to get any chlorine shock on your skin and always wash hands with plenty of water after handling.

Step Five:

Let it Work

Let the chlorine shock work its magic for a while (around 24 hours). Test the spa again before using with a chlorine test strip to ensure chlorine is back to a safe level for bathing.
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