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

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

The time you should wait before you go in a hot tub after giving it a shock treatment varies depending on several factors.

So the real but unhelpful answer is – it depends!

It can take 20 minutes to 24 hours if you give 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.

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 unsure, 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:

• dichlor shock (dichloroisocyanuric acid)
• cal hypo (calcium hypochlorite)

Most brands of spa shock contain dichlor, and that is 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, you will need to wait longer than if you had just given it a normal weekly dose. The chlorine levels could take 24 hours 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 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. I would use a non-chlorine oxidizer once a week.

Recommended shock products

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

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 cloudier the water, the longer it will take for the shock treatment to thoroughly cleanse it, as a higher dosage of shock will be required. 

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

3. How often you shock your hot tub

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

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, the water will take less time to reach its normal bathing levels. 

Read: How often to shock a hot tub

How long after adding chlorine can you test?

When adding 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, you could test the hot tub water after 2 hours. Obviously, if the chlorine level is above 3ppm, you should wait another few hours before testing again.

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 chlorine poisoning.

Can you overshock a hot tub?

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

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

If you overshock your hot tub, several steps 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, 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 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?