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How Long After You Shock Your Pool Can You Swim Again?

After winter, when it’s time for you to open your pool again, it’s likely that you’ll need to shock it first. This is likely why a lot of people wonder how long they need to wait before they shock the pool to enter it again. Despite this, you may want to enter your fibreglass pool as soon as possible.

What is Shocking Your Pool?

Before you can swim in your pool again, after the winter months, you’ll need to shock your pool first because the pool is exposed to contaminants that normal sanitation methods may not be enough to contend with. This includes urine, perspiration, leaves, cosmetics, algae, as well as other foreign matter that the pool is exposed to constantly.

For this reason, it’s necessary for you to shock your pool every one to two weeks. When you shock your pool, you ensure that these contaminants are kept under check. It also decreases the stress experienced by your filtration system, allowing your normal sanitation methods to take care of the pool. These stress factors can also affect your pool water, even when you’ve kept it close for the winter.

Adding shock to the pool water results in the contaminants in the water getting killed. It can also help restore the balance in the water. When you shock your pool, you engage in a cleaning process that is amplified. This means that the amount of chlorine used is much more than what you would use during a normal pool cleaning.

How Long After Shocking Your Pool Can You Swim?

The general rule of thumb is that you can swim in your pool for around twenty four hours after shocking it. To be extra safe, you can consider testing the chlorine, as well as the pH levels in the water, before you enter the pool. You can do this with the help of a chemical test kit. The level of free chlorine in the water should be at least 3ppm or less.

Algae Bloom and Pool Shock

In case you’re dealing with an algae bloom, then you should ensure that the algae has been completely removed before you swim in the water. Depending on how serious the algae bloom in your pool is, the amount of time it will take to be free of algae can change.

You should consider getting in touch with a pool professional to deal with a severe algae bloom in your pool. After you shock your pool, the chemicals you add to the water will start the hard work related to eliminating bacteria, as well as other contaminants.

When Should You Shock Your Pool?

Shocking your pool means adding either chlorine or other pool chemicals to your swimming pool. You do this in order to increase the level of free chlorine in the water. The idea behind shocking your pool is to raise the level of free chlorine to a point where foreign contaminants such as bacteria and algae are killed.

Just because you can smell chlorine coming from a pool, that doesn’t mean that the water is clean. A clean pool actually tends to be odourless. When you can smell chlorine coming from a pool, this usually means that the water in the pool hasn’t been properly treated. The odour you smell comes from chloramines, another name for which is combined chlorine.

When chlorine is found in the pool water mixed with nitrogen found in sweat, urine, and even body oils, then chloramines are formed. However, you’ll need to go by more than just smell to decide when you should shock your pool.

Consider shocking your pool when:

  1. Algae or algae blooms are present in your pool
  2. Free chlorine levels in your pool are at zero
  3. The chloramine level in your pool is more than 0.5 parts per million

The Steps Involved With Shocking Your Pool

The goal behind shocking your pool is to raise the level of free chlorine in the water to ten times that of the combined chlorine. The point where this happens is referred to as breakpoint chlorination. Ideally, you should shock your pool either at dusk or during the nighttime.

Otherwise, the rays of the Sun will affect the chlorine that is unstabilized, essentially eating it up. When you shock your pool at a time when the Sun’s rays are not visible, then the chemicals can do their job properly.

Here is how you should shock your pool:

  1. Test the Water

Begin by checking to see what the pH level of the water in the pool is. You can do this with the help of a pool test kit. With a pool test kit, you can measure the FC, as well as the TC of the water. Subtract the FC from the TC gives you the CC. The CC is how much chlorine you should add to the pool.

  1. Mixing Pool Shock

Refer to package instructions found on the pool chemical you’ve purchased to mix the right proportion of pool shock.

  1. Adding Pool Shock

There are some kinds of pool shocks that are granular that can directly be added to the pool. Usually, you’ll need to mix it with water first. Even if you’re using granular pool shock, consider mixing it in water beforehand. You can also use liquid pool shock.

The pool pump should be running when you pour in the pool shock. Pour it in around the pool’s edges.

  1. Testing the Water

After you add pool shock to your fibreglass pool, let the pool pump run for at least six hours. After this, before you swim in the pool, you should consider testing the water in the pool.

When the chlorine levels in the water lower to anywhere between 1 to 3 parts per million, you can use your pool.


You should wait at least a day before you swim in your pool after you’ve shocked it. Remember to wear safety glasses, as well as gloves, when you’re mixing and working with pool chemicals. If you require more help, don’t hesitate to reach out to our pool builders melbourne as they can advise you.

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