How To Lower Free Chlorine In Hot Tub

If you knew about these simple methods of reducing free chlorine in hot tubs, you wouldn’t be bothered by it. The only concern is that it’s not safe for your health and spa. 

You can lower the free chlorine in your hot tub by any of the following methods:

  • Exposure to sunlight
  • Heating the water
  • Adding chlorine neutralizer
  • Diluting with fresh water

So, how do you lower free chlorine with these methods?

  • Exposure to sunlight

The chlorine in your hot tub depletes faster when the water is directly exposed to the UV rays of sunlight. This is the easiest and most natural way to lower the excess free chlorine in your spa.

Even without the sunlight, the free chlorine level will naturally drop. Exposing it to sunlight only makes it drop faster. So, open the hot tub and allow it to run for about 6–24 hours. 

  • Applying heat

If you can remember your high school chemistry, heat is one of the factors that makes chemicals react faster. So, when you heat the water in the hot tub, the free chlorine reacts faster. 

However, hot tubs have the right temperature to facilitate chemical reactions. More so, the heat makes more water vapor leave the spa. Running the jet facilitates the whole process.

The water vapors that are leaving the spa don’t leave alone. The chlorine molecules usually escape the hot tub through the vapor. That makes the free chlorine deplete faster.

  • Using chlorine neutralizer

You will be able to purchase a chlorine neutralizer at the pool stores around your neighborhood. Sodium thiosulfate is the most common one you can find in the store. 

Once you get it, follow the instructions on the pack to lower the free chlorine. Generally, you add the crystal granules and run the hot tub jet. Allow it to circulate for a few hours before you test the water.

  • Dilute the water

You can drain some of the water from the hot tub and refill it with fresh water. But you need to be careful with this method because it usually alters the chemical balance of the water.

So, after refilling it with fresh water, you need to test the pH, alkalinity, stabilizer, etc. Adjust anyone that needs correction, and enjoy your spa.

How long does it take to lower chlorine in a hot tub?

Well, this depends on the amount of chlorine you added to the hot tub. On average, it takes about 30 minutes to 4 hours for the chlorine to break down.

But, if you shock the hot tub, it can take up to 24 hours before you can start using it again. This is so because the shock introduces a high level of chlorine to the spa.

Nonetheless, whether you wait for 30 minutes or 24 hours, make sure that you test the water before using it again.

What happens if you have too much chlorine in your hot tub?

Is high free chlorine harmful? Having too much chlorine in your pool or hot tub can damage its components. Moreover, it is not safe for the swimmer.

It can cause rashes, chlorine poisoning, eye irritation, burning of the nose, difficulty breathing, etc. 

Prolonged exposure can cause further damage to your health. People with respiratory issues should avoid it by all means.

What to do if total chlorine is higher than free chlorine?

Normally, total chlorine should be slightly higher than free chlorine when the chlorine starts to react in the water.

When chlorine reacts with other compounds, it forms a new bond that gives rise to combined chlorine

Total chlorine is the sum of free chlorine and combined chlorine. However, the combined chlorine in the hot tub should not be more than 0.2 ppm.

Once the value of combined chlorine exceeds 0.2 ppm, the best thing to do is to shock the pool.

So, if you notice that the total chlorine is higher than the free chlorine, you need to confirm that by using a DPD kit to run a test. The test will help you determine the value of total chlorine and free chlorine.

Then find the combined chlorine by subtracting the free chlorine from the total chlorine.

Combine chlorine = total chlorine – free chlorine.

If the value is greater than 0.2, it shows that you need to treat the hot tub with a shock.

What does free chlorine mean in a hot tub?

Free chlorine is chlorine that has not reacted with other compounds. It is the active chlorine that kills bacteria in a hot tub.

When free chlorine reacts and forms new bonds with other compounds, it becomes combined chlorine. For instance, when chlorine reacts with ammonia, it forms chloramine, which is not effective enough to kill bacteria.

So, if you are wondering why free chlorine is important, the above point is the reason. With free chlorine, the total chlorine in your spa will not be able to disinfect. That means they are no longer effective.

What neutralizes chlorine?

If you are looking for the right chemical to neutralize chlorine in your hot tub, go to any pool store close to your location and ask for sodium thiosulfate. 

You can go to the search bar and type “pool store near me“. It will help you locate the store in your area.

Sodium thiosulfate is popular among pool and hot tub owners. There are other neutralizers like hydrogen peroxide, but it’s the most popular one. Besides, it is very effective.

Does pH plus reduce chlorine?

No, pH plus does not reduce chlorine in hot tubs or pools. Chlorine performs better at a pH of 7.45.

If pH plus is used to increase pH when it goes down, it means that pH can indirectly improve the effectiveness of chlorine.

However, if the pH plus increases the pH above 7.45, it shows that the pH plus can also reduce the effectiveness of chlorine indirectly.

But, it doesn’t mean that the pH plus reduces or raises the chlorine level in your hot tub.

Should free chlorine equal total chlorine?

As we stated earlier, free chlorine is the chlorine that reacts with other chemical compounds in order to disinfect the water.

So, when free chlorine starts reacting, it should not be equal to total chlorine because the reacted free chlorine molecules have been converted to combined chlorine.

Total chlorine is the sum total of free chlorine and combined chlorine. So, it is normal for total chlorine to be slightly higher than free chlorine.

Can you enter a hot tub with no free chlorine?

No free chlorine literally means no sanitizer. It is not advisable to use a spa that doesn’t have an active sanitizer.

Once the sanitizer in your hot tub stops disinfecting, bacteria and other pollutants can easily enter the spa and multiply. As the spa becomes infested with microbes, it’s no longer safe for the owner.

Before you can use such a hot tub, you need to shock it very well.

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