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

Shocking your hot tub water is something every owner has to do on a weekly basis. So how long does it take for the chlorine levels to become safe again?

After adding chlorine shock, it takes approximately 24 hours before the levels are safe for bathing. In some instances, it may take up to 48 hours. After using non-chlorine shock, you only need to wait 20-30 minutes. Always use a test strip before getting back in to ensure it is safe.

Using a hot tub with high chlorine levels is dangerous, so you need a reliable way of testing. There are several different options to test your water, which I’ll take you through later on.

Chlorine vs non-chlorine shock

Chlorine shocks are more suitable for hot tubs that are used frequently, especially by a large number of people. They are strong enough to disinfect your spa water.

On the other hand, non-chlorine shocks won’t disinfect your spa water; however, they help the free chlorine to work more efficiently and destroy unwanted bacteria.

In addition, chlorine shocks are more concentrated than non-chlorine shocks and, as such, require a longer waiting time after applying them in your hot tub.

Chlorine shock wait time

Due to the high concentration and slow-acting nature of chlorine shocks, they usually take about 24 hours before they’re fully activated.

However, if the hot tub is heavily infested with algae, the shock may take longer than 24 hours to work effectively. In some cases, removing the bacteria present in the water could take as long as 48 hours.

Another scenario where you might have to wait 48 hours is if you accidentally add too much shock to the water. To be safe, ensure you test the water after the wait time is over. Alternatively, you can use a neutralizer to reduce the chlorine levels quickly.

Furthermore, make sure you turn on the hot tub’s jets and take the cover off for 20 minutes after applying the chemical shock. 

This process will allow the chemical to circulate and oxidize properly. It will also protect the spa’s pillows from damage. The same rules apply to non-chlorine shocks.

Non-chlorine shock wait time

Non-chlorine shocks take about 15-20 minutes to fully activate in the hot tub water, which means you can use your spa within half an hour after completing the shocking process.

The reason non-chlorine shock has a much shorter wait time than chlorine-based shock is that the lack of chlorine means it is less harmful to the skin. Still, you should test the water before using the hot tub. 

Safe chlorine levels in a hot tub

According to the Centers for Disease Control and Prevention, chlorine levels should be maintained within a range of 1-3 ppmOpens in a new tab. for safe hot tub use. 

Maintaining safe chlorine levels is very vital as a failure to do so can lead to adverse health effects. For instance, chlorine levels above 5 ppm can cause eye and skin irritation, as well as respiratory issues.

Another thing to look out for is the pH level of your water. If the pH level is greater than 8.0, the ability of free chlorine to destroy germs decreases. If the pH level is lower than 7.0, the ability of free chlorine to destroy germs increases, but the hot tub pipes are more likely to corrode.

Therefore, you want to keep the pH level in the 7.4-7.6 range as this is the safest range for killing germs, maintaining the lifespan of the pipes, and preventing hot tub-related illnesses. 

The best way to maintain safe chlorine and pH levels is by regularly testing and adjusting the water chemistry. Depending on the result, you may have to add or reduce chemicals in the hot tub.

In addition, never use a hot tub too soon after shocking it. This could lead to health issues like wheezing, chest tightness, blisters, burning, and nausea.

How to check chlorine levels

To check your chlorine levels, you can use two methods. The first is to use a DPD test kitOpens in a new tab. to measure the free chlorine. DPD stands for N,N-Diethyl-1,4-phenylenediamine Sulfate.

You should note that if the concentration of chlorine in the water is greater than 10 ppm, the test might result in a 0 ppm free chlorine.

An alternative method for checking chlorine levels is by using a test kitOpens in a new tab. (more accurate) or test stripsOpens in a new tab. (less accurate). But you should note that both these methods are less accurate than using a DPD kit. 

To use a test strip, dip it in the water and pull it out quickly. Next, hold the strip still for about 15 seconds without shaking it. Then compare the resulting color with the color guide on the test strip package.

If you decide to use a test strip, ensure no fluid or dirt spills on it so as not to interfere with the test results. After using the test strip, make sure you keep it back in its waterproof container.

Tips for less waiting time when shocking your hot tub

Waiting for chlorine levels to reduce can sometimes be a hassle. But you can avoid this waiting time by simply adding a little shock to the hot tub after each use.

This is very effective, especially because most people use their hot tubs once a day, giving the chemicals 24 hours to dissipate to safe levels.

Joshua Milton

Joshua Milton is a seasoned hot tub enthusiast. With many years of experience in the industry, he offers valuable insights on hot tub maintenance, health benefits, and relaxation techniques.

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