How Long After Shocking a Hot Tub Can You Use It?




It is important that you know how long to wait after shocking a hot tub or spa. Using a hot tub too soon after it is shocked can lead to problems, but not with the hot tub itself, problems for hot tub users.

The time that you should wait before you go in a hot tub after giving it a shock treatment differs depending on a number of factors.

So the real but unhelpful answer is – it depends!

It can range in time from 20 minutes and anything up to 24 hours if you gave it a heavy shock using a chlorine-based hot tub shock. That is rather a broad time range so I will be more specific in the rest of the post.

how long to wait after shocking hot tub

Key Takeaways

  • How long after shocking a hot tub can vary from 20 minutes to 24 hours
  • The best way to know when you can get back in the hot tub is to test the water to check the chlorine level is 3ppm or less
  • If you use a non-chlorine oxidizing shock you can use the hot tub again after as little as 20 minutes

Factors that affect how long to wait after shocking a hot tub

1. Type of shock

The type of shock you use will be the most important factor in deciding how long to wait before you use the hot tub again.

Generally, you will have to wait longer before it is safe to use when using chlorine shock than non-chlorine shock.

Always read the labels of the shock product you have bought. If you are not sure, then either look the product up online or ask a professional.

Chlorine shock

The most usual type of shock to use with a chlorine hot tub is, unsurprisingly, chlorine. There are two main types of chlorine shock which are:

Most brands of spa shock contain dichlor and that would be the type I would recommend. Cal hypo is more suitable for shocking swimming pools.

If you have given the hot tub a very strong shock (super chlorinated) due to a problem with the water then you will need to wait longer than if you have just given it a normal weekly dose. It could take as long as 24 hours for the chlorine levels to reduce to safe, normal levels.

You should test the water using a test strip or some other test method to check the chlorine levels before using it. You should wait until the chlorine levels are 3 ppm (parts per million) or less.

Non-chlorine shock

In most cases, when using a non-chlorine shock (which is an oxidizer) you can get back in quite quickly. It is ideal to use if you test your water before a spa party and realize you need to shock but have little time before the party.

Many non-chlorine shocks act quickly so you can use the hot tub again after as little as 20 minutes.

However, although non-chlorine shocks are fast acting they will not kill algae or some bacteria so they are not a long-term solution.

Bromine hot tubs

In a bromine hot tub, you can use either chlorine based or a non-chlorine oxidizer shock. Personally, I would use a non-chlorine oxidizer once a week.

I recommend using SpaGuard Spa Shock or SpaGuard Spa Shock-Oxidizer

SpaGuard Enhanced Spa Shock 6#

SpaGuard Spa Shock-Oxidizer, 7lb

2. How dirty the hot tub is

As you can probably imagine, the more you use the hot tub, the dirtier it will get.

Also, not cleaning it or shocking the hot tub for a while will leave more bacteria and other contaminants inside the water. Often you can see this by the color of the water.

The dirtier and more cloudy it is, the more time it will take for it to be thoroughly cleansed by the shock treatment as you will have to put a higher dosage of shock in the water. 

The higher the concentration of the shock product, the longer it often takes for the water to stabilize to normal levels again. The normal levels are necessary for your bathing to be safe and healthy.

3. How often you shock your hot tub

The more often you shock the hot tub, the cleaner the water will be.

Therefore, when you do your regular shock routine, using a lot of spa shock in a high concentration will most likely not be necessary.

If you use less spa shock, and at a lower concentration, it will take less time for the water to reach its normal bathing levels. 

Read: How often to shock a hot tub

How long after adding chlorine can you test?

how long after adding chlorine can you test

When you have added chlorine shock to the pool you should run the jets for an hour or two to ensure the chlorine is spread throughout the hot tub and can do its job.

If you have not added a large amount of chlorine then you could test the hot tub water after 2 hours. Obviously, if the chlorine level is above 3ppm then you should wait another few hours before testing again.

Recommended Test Strips

AquaChek 7-Way Pool and Spa Test Strips - Silver Pool Test Strips For pH, Total Chlorine, Free Chlorine, Bromine, Alkalinity, Total Hardness, and Cyanuric Acid - Water Quality Testing Kit (100 Strips)

Aquachek 7-way test strips

I use these test strips that can tell you the total chlorine/bromine, free chlorine, pH, total alkalinity, CYA and hardness levels.

Is it safe to go in a hot tub with high chlorine?

Using a hot tub when the chlorine levels are above 3 ppm can lead to:

  • red and sore eyes
  • itchy skin
  • respiratory problems

Some people are more susceptible to these effects than others. Some bathers may experience itchy skin in a hot tub due to the jets rather than chlorine levels.

At higher chlorine levels (5 ppm or above) it could possibly lead to what is known as chlorine poisoning.

Can you over shock a hot tub?

You can certainly over shock a hot tub by adding too much chlorine shock.

Over shocking a hot tub can lead to various issues such as cloudy water, foul odors, discolored water and if you were to go in it then itchy skin and stinging eyes.

If you over shock your hot tub there are several steps that can be taken to rectify the situation.

  • Do nothing. Just leave the cover off the hot tub and allow the chlorine to dissipate. If the hot tub is outside and in the sun then the chlorine level will drop quicker. Test the water and do not go in until the chlorine level has returned to 3ppm or less.
  • Drain. You could completely drain or partially drain the hot tub and refill it with fresh water.
  • Neutralizer. You could use a chlorine neutralizer (such as BioGuard Chem Out). Add it to the pool and run the jets for a few hours and then retest the water.

Following the instructions for the shock treatment carefully and not exceeding the recommended dosage is crucial.

If your hot tub is constantly over shocked then it could lead to problems – Can Too Much Chlorine in Hot Tub Damage it?

Hot Tub Maintenance Course

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How Long After Shocking a Hot Tub Can You Use It? 1

Can you go in a shocked hot tub?

You should not go in a shocked hot tub until the chlorine levels have reduced to 3 ppm or less otherwise bathers can experience sore eyes and itchy skin.

Is spa shock the same as chlorine?

Spa shock is different from the normal chlorine you use in a hot tub. Spa shock is unstabilized whereas normal chlorine is stabilized. Stabilizer is CYA (cyanuric acid) which prevents chlorine from being used too quickly.

Will shock lower pH in hot tub?

Pool shock will not directly lower the pH in a hot tub but the pH could be altered as a side effect. You should test the pH after the shock has done its job and readjust if necessary.

How many times can I shock my hot tub?

Generally you would only shock a hot tub once per week. If the hot tub is so dirty that after shocking it is still dirty then you would be better advised to empty it and refill.

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