Expert Advice For Too Much Chlorine In Hot Tub

Published on

April 16, 2023

Too much chlorine in hot tub water is a problem common among many hot tub owners. It comes with various issues that can become dangerous to your health, such as chlorine poisoning.

Maintaining proper water chemistry sounds complicated, but this article will prove you wrong. Keeping excess chlorine at bay has never been easier!

In this article, we explore what lies behind increased hot tub chlorine levels, how to detect them, and what to do to keep your hot tub balanced.

What Are the Recommended Chlorine Levels For Spa Water?

The optimal free chlorine concentration for spa water is 3 ppm. This concentration is high compared to the one recommended for pool water, which is 1 ppm of chlorine.[1] Combined chlorine in hot tub water should be below 0.5 ppm.

When discussing chlorine or bromine levels, it's essential to consider the difference between the free amount, the combined amount, and the total amount. The following table lists the types of chlorine in spa water.

Type Description Recommended Amount
Free Chlorine The chlorine capable of killing bacteria and other contaminants 3 ppm (ideal)
Combined Chlorine The chlorine developed during the sanitation process < 0.5 ppm
Total Chlorine Free chlorine + combined chlorine < 3.5 ppm

Hot water is a great environment for pathogens to multiply. As a result, it is important to ensure that the water is free of bacteria. This means running a weekly sanitizing routine with chlorine or bromine.

These chemicals are effective disinfectants, but chlorine is the most common among spa owners. Whether it's chlorine or bromine, or even free chlorine, you should always maintain a check and balance.

Chlorine[2] for hot tubs comes in various forms:

  • Sodium hypochlorite[3][4]
  • Salt chlorine
  • Calcium hypochlorite
  • Chlorine tips
  • Sodium Dichlor granules
  • Trichlor tablets

Sodium Dichlor[2] granules are the most effective for keeping a hot tub clean. Granules dissolve more evenly than chlorine tablets. This ensures that there is no area with lower chlorine levels than recommended.

Trichlor tablets are not recommended by the CDC for hot tubs because of their cyanuric acid concentration.

How Much Is Too Much?

If your test strip shows a free chlorine concentration higher than 3 ppm, that is too much. You should check the levels every time you add chlorine to your hot tub.

Whether you use chlorine or bromine for hot tub maintenance, you must keep in mind the correct amount of sanitizing agent to avoid damaging the hot tub components and protect the users' health. High bromine levels are not as easily detected as with chlorine but can cause damage too.

Chlorine is an important component of hot tubs, as it helps to keep the water clean and free of bacteria and other contaminants.

High chlorine concentrations can be harmful to your health. They can lead to serious health problems, such as:

  • Respiratory problems
  • Nausea 
  • Vomiting

In extreme cases (up to 10 ppm), it may even result in death. Taking action quickly can help avoid any potentially serious health problems.

How much is too much cholorine in your hot tub?
How Much Is Too Much?

Signs You Have Too Much Chlorine In Your Hot Tub Water

Going into a hot tub with a high amount of chlorine might get you in trouble, but the signs can help you see if the water has high chlorine levels. This happens when you use too much sanitizer.

The signs you have high chlorine or bromine levels in your hot tub are not always similar.

Here are five signs of a high chlorine concentration in spas:

  1. Cloudy water
  2. Strong chlorine smell
  3. Irritated eyes during and after bathing
  4. Dry, itchy skin during and after bathing
  5. Respiratory problems during and after bathing

1. The Hot Tub Water Is Cloudy

High bromine levels don't cause cloudy water. The water is crystal clear even if the water chemistry is unbalanced. But chlorine elevated levels cause the water to become cloudy.

Other factors, such as high pH or high calcium hardness levels, can also cause cloudy spa water. Use a test strip to make sure of the cause.

2. A Strong Chlorine Smell Comes From the Hot Tub

If you can smell chlorine near your hot tub, it can indicate a high quantity of chlorine in the water.

When you have too much chlorine in the spa water, it can off-gas and cause an unpleasant smell.

3. Your Eyes Are Red and Irritated After Being in the Hot Tub

When the water in your hot tub has high chlorine levels, you can experience irritated and red eyes after or during bathing.

Chlorine can irritate the eyes of people who have chlorine sensitivity, even if the concentration is not too high. This is why it is important to test the water chemistry before reducing the chlorine amount.

4. You Have Dry, Itchy Skin After Being in the Hot Tub

Excess chlorine causes skin irritation which can manifest as dryness and itchiness.

When chlorine affects the chemical balance of spa water, it can also cause brittle hair.

5. You Have Respiratory Problems After Being in the Hot Tub

When inhaled, chlorine can irritate the lungs and cause difficulty breathing. People with asthma or other respiratory problems should be especially careful when using hot tubs with high chlorine.

What Causes Too Much Chlorine in Hot Tub Water?

The main reason you have elevated amounts of chlorine in your hot tub water is using too much sanitizer and shocking agents.

Chlorine has the property of turning into a gas at room temperature. When it dilutes in the water, this halogen eventually evaporates. This is not a reason to add too many chlorinating granules because it doesn't evaporate as quickly as you might think.

How Fast Does Chlorine Dissipate from Hot Tub Water?

Chlorine is an effective disinfectant, but it doesn't last forever.

The rate at which chlorine dissipates depends on various factors, including the water temperature and the amount of sunlight exposure due to the heat it generates.

High chlorine levels can drop by half within the first two hours of hot tub use.

After that, they continue to decline at a slower rate until they reach zero. But in most cases, when you accidentally add a higher chlorine concentration, it may not dissipate as quickly. In such cases, you need to lower the chlorine concentration manually.

Testing a Hot Tub To Check Chlorine Levels

Chlorine or bromine are not the same in terms of sanitation but are measured similarly. Bromine or chlorine levels must remain within the recommended limits and it's essential not to reduce them excessively. For better chemical control, there are various ways to act.

If you suspect you have elevated chlorine levels in your spa water, make sure to test your spa water chemistry. There are several ways to do this, but one of the most common methods is to use a test strip.

Testing a Hot Tub To Check Chlorine Levels
Testing a Hot Tub To Check Chlorine Levels

Test Strips

Chlorine or bromine test strips measure the amount of free bromine or chlorine present in the water. You can find them at most hardware stores or pool supply stores. Test kits offer information on the combined chlorine levels also.

Chlorine test strips are easy to use. You dip them into the water and wait a few seconds for them to change color. The strip gives a reading that tells you how much chlorine is in the water.

Digital Chlorine Tester

Another standard method to test chlorine concentration is using a digital chlorine tester.

Digital chlorine testers work similarly to test strips but are more accurate and give you an instant reading. They are a bit more expensive than test strips but are worth the investment if you plan to use your hot tub regularly.

In case you are concerned about measuring the chlorine levels in your hot tub, it is always best to consult a professional.

How Often To Test the Chlorine Level of Your Hot Tub?

You should test the chlorine levels in your hot tub at least once weekly.

If you use chlorine sanitizers frequently, you may need to test it more often to ensure the levels remain balanced.

It is also a good idea to test the chlorine levels after adding any chemicals to the water or if there have been any changes in the water's appearance or clarity.

Six Easy Ways to Reduce Chlorine Levels in Hot Tubs

If you observe any of the signs indicating high chlorine levels, reducing the chlorine amount in your hot tub is essential for bathing safely.

Here are six ways to safely reduce chlorine in hot tub water:

  1. Evaporation
  2. Neutralization
  3. Oxidation
  4. Dilution
  5. Drain/refill
  6. Filtration

1. Let it Lower Automatically (Through Evaporation)

Not using your hot tub until chlorine levels go down by themselves is the easiest method.

All you have to do is let the water evaporate, and the chlorine will dissipate. Chlorine concentration will naturally decrease if the hot tub is not in use.

In case you use a chlorinator, make sure to turn it off until the chlorine concentration lowers to a safe level.

2. Use A Chlorine Neutralizer

If you are experiencing a high chlorine amount, leaving it to lower by itself doesn't happen fast enough. In this case, you can act in various ways to help speed up the process.

Another easy way to reduce the chlorine concentration is to use a chlorine neutralizer. Chlorine neutralizers are chemicals added to the water that bind with the chlorine and remove it.

3. Oxidizing Agents Reduce Chlorine From Hot Tub Surfaces

Did you know that adding chlorine can help you remove chlorine? This may sound counterintuitive, but it’s true. The secret lies in the type of chlorine you add.

An oxidizing agent helps break down the chlorine molecules and remove them from the water.

Here is a list of the most common oxidizing agents useful for reducing chlorine concentration in hot tubs:

  • Calcium hypochlorite
  • Sodium hypochlorite
  • Potassium permanganate
  • Sodium thiosulfate

You can find these chemicals at most pool supply stores.

4. Use Fresh Water to Dilute the Chlorine Levels

If you are in a pinch and need to reduce chlorine levels quickly, you can use freshwater to dilute the hot tub water. This is not a long-term solution, but it can help in a pinch.

Simply add fresh water to the hot tub until the chlorine concentration safely decreases.

5. Drain and Refill the Hot Tub

If you are still having trouble reducing chlorine levels, you may need to drain and refill the hot tub. This should be done every few months to keep the water clean and fresh.

When you drain the hot tub, clean it thoroughly before refilling it with fresh water.

6. Use A Chlorine Filter

You may consider using a chlorine filter if you are looking for a long-term solution for a high chlorine level.

Chlorine filters are designed to remove chlorine from the water as it circulates through the filter. This is a great way to keep chlorine concentration low without constantly adding chemicals to the water.

Chemicals That Reduce High Chlorine Levels

A less common way to reduce the chlorine level of your hot tub water is to use chemicals that are usually used for other purposes, such as vitamin C and hydrogen peroxide.

We recommend using chemicals as a last resort, as they can be harsh on the skin and may not be necessary if you use other methods.

Chemicals That Reduce High Chlorine Levels

Vitamin C

One of the most popular chemicals used to reduce chlorine levels is vitamin C. Vitamin C is a natural oxidant that can help break down chlorine molecules.

You can find vitamin C tablets at most pool supply stores. Simply dissolve the tablet in the water and let it circulate for a few hours.

Vitamin C comes in other forms also, such as powder or liquid.

Ascorbic acid is another name for vitamin C, so don't skip it thinking it is a different chemical.

Hydrogen Peroxide

Hydrogen peroxide is another oxidizing agent that can reduce the amount of chlorine in your hot tub water. Hydrogen peroxide can be found at most drugstores.

Simply add hydrogen peroxide to the water and let it circulate for a few hours.

How Long Does It Take For Chlorine Levels To Drop?

The amount of time it takes for chlorine levels to drop depends on a few factors, such as:

  • The water temperature
  • The type of chlorine in the water
  • The amount of chlorine in the water

In most cases, it takes 24-48 hours for chlorine concentration to drop significantly. If the water is too hot or the chlorine levels are too high, it may take longer for the chlorine to evaporate.

You can speed up the process using a chemical oxidizing agent or diluting the water with fresh water.

Using the O-Care Weekly Spa Care can reduce the amount of chlorine you add to your hot tub water by 78%. This helps you keep chlorine levels at bay.

How Long Does It Take For Chlorine Levels To Drop?


Many enjoy soaking in a hot tub, but too much chlorine can be harmful. There are a few ways to reduce the chlorine amount in your hot tub, such as using a chlorine filter or adding chemicals to the water. You can also dilute your spa water with fresh water if the chlorine levels are too high.

Chlorine testing is important to make sure that the levels are safe. If you have concerns, contact a pool or hot tub professional.

FAQs about Chlorine in Hot Tubs

What Happens if Chlorine Is Too High in a Hot Tub?

If chlorine levels are too high, you can experience eye and skin irritation. Excess chlorine in a hot tub can also cause severe health issues. Chlorine can cause nausea, vomiting, and diarrhea.

In worst-case scenarios, you can die of chlorine poisoning

Why is Chlorine Testing Important?

Chlorine testing is important because it helps you detect high and low chlorine levels. It's essential to keep chlorine levels safe to avoid health issues and the deterioration of your jacuzzi. Chlorine testing also helps ensure that your hot tub is clean and bacteria-free.

Does Inviting More People To Use Bath Tub Decreases Chlorine?

The more people use your hot tub, the more chlorine will be used. This doesn't necessarily mean that inviting more people decreases chlorine levels. It all depends on how often you use the hot tub and how well you maintain it.

Does Using a Hot Tub Cover Help With Chlorine levels?

A spa cover can help reduce evaporation, which eventually leads to lower chlorine levels. A cover also shades the water from the sun, which can help prevent algae growth.