Home » Too Much Chlorine in Hot Tub | Is it Dangerous?

Too Much Chlorine in Hot Tub | Is it Dangerous?

Have you put a bit too much chlorine in your hot tub and wondered what to do now? Are you curious about how to fix it and if it is dangerous to your health? Let’s find out!

Man using chlorine tablet for hot tub
Man using chlorine tablet for hot tub

The recommended chlorine level for a hot tub is at least 3 ppm. At higher levels, such as 5 ppm or more, the chlorine level can be harmful to your skin and dangerous to your health – do not go in. 

Chlorine is such an important chemical to have in your hot tub to ensure it is sanitary to be in, but it can be dangerous if the chlorine level is not correct. Find out the signs of an overly chlorinated hot tub, what to do if you have been in, and ways to fix the chlorine level. 

How Much Chlorine Is Too Much And What Are The Signs?

Regardless of how too much chlorine got into your hot tub, know it CAN be fixed. You can bring the chlorine down to a safe level so you can enjoy your hot tub again. 

To test your hot tub’s chlorine levels if you are only presuming you have put too much in, you can use a liquid test kit or test strip to find out the exact levels and to know what your working with. Be sure to follow the instructions and take a sample away from the jets.

Recommended Safe Chlorine Levels For A Hot Tub

According to CDC (Centers for Disease Control and Prevention), the recommended amount of free chlorine concentration added to a hot tub should be at least 3 ppm (parts per million). 

If the chlorine levels are higher than that, such as at 5 ppm, it may begin to be harmful to your skin. Chlorine may damage prescription glasses too, if you wear them in. At even higher levels, around 6-7 ppm, it can be dangerous for your health to be in the hot tub as chlorine poisoning can occur. 

Alternatively, if it is less than 3 ppm, the hot tub may not be sanitized enough, which isn’t good either. So, you can see how it can be a bit of a fine art getting the chlorine levels just right so it is safe to be in, but how important it is! 

Chlorine Level Signs

In the table below, you can see the differences between the signs of a hot tub that has chlorine levels that are too high and too low. This gives you an indication of the chlorine levels if you do not have a test kit or test strip to check. 

Noticing Chlorine Level Signs In A Hot Tub

SignsChlorine Level Too HighChlorine Level Too Low
SmellNo smellMay notice a musty odor or there is a strong smell of “chlorine” (which is really chloramines).
Skin, Eyes, and HairSkin become irritated, itchy, inflamed, or dry. Eyes may sting from the chloramines. Hair may become brittle.Bacteria can cause rashes, clogged pores, and other skin issues.
Feeling unwellFeel nauseous or difficulty breathing due to the excess chlorine vaporizing and being inhaled.Harmful bacteria and microorganisms can grow and make you feel unwell.
SwimwearSwimwear’s color starts to fade due to the bleaching effect of chlorine. Plus, elastic wears out. Both happen with prolonged exposure.Notice slime attaching to your swimwear.
Water May appear cloudyMay appear cloudy, foamy, or have a green, slimy film on the surface.
Hot tub appearanceStaining and etching on the acrylic shell.Slimy and algae are beginning to form.
Hot tub equipmentPremature wear on the pumps, seals, filters, etc.Biofilm builds up in the plumbing and inside the tub.

Signs Of a Healthy Level Of Chlorine In Your Hot Tub

Here are some key signs that your hot tub has the correct amount of chlorine in it.

  • The water is clear 
  • There are no smells or odors
  • The hot tub’s appearance and equipment look good and function well
  • Your swimwear is not affected (just wet!)
  • The water feels fine on your skin, and you don’t feel unwell

If you recognize these signs, then great, it is likely your chlorine levels are good, but I would still advise testing and chlorinating your hot tub regularly.

What Do I Do If I Have Swum In High Levels Of Chlorine?

If you are aware that there is too much chlorine in the hot tub, do not go in! It can be very dangerous to your health, so don’t risk it.

If you already have been in and are feeling unwell, remove your swimwear and wash your body to wash the chlorine off. Rinse your eyes with fresh water and get into some dry, clean clothes. If you think you may have chlorine poisoning, then go to the hospital immediately. 

3 Ways To Lower The Chlorine Level In Your Hot Tub

Chlorine dispenser for hot tub
Chlorine dispenser for hot tub

There are multiple ways to reduce the chlorine level in your hot tub, so don’t worry, you will be able to enjoy a long hot soak soon enough! 

If you haven’t stopped adding chlorine to the hot tub, make sure you do that now, and remove the chlorine floater if you have one. Let’s explore the different methods you can use to bring the chlorine levels back into balance.

1. Use a Chlorine Neutralizer 

One way to reduce chlorine levels in your hot tub quickly is by using a chlorine neutralizer such as sodium thiosulfate. Similar options are sodium sulfite, sodium bisulfite (don’t confuse this with sodium bisulfate/pH down), and sodium metasulfite. 

If you need to change the chlorine levels ASAP, this is the best method to use, so I would suggest having a chlorine neutralizer on hand for times like these if you do own a hot tub. It will lower the amount of free chlorine and chloramines in the water faster than anything else will.

I would recommend using Cesco Sodium Thiosulfate which is very effective and only costs between $10 – $30, depending on the weight of the bag you get. It will generally work within a matter of hours.

Be sure to read the instructions carefully, add the neutralizer slowly and gradually, and don’t overdo it. It’s best to add too little than too much! 

Keep the jets in the hot tub on and let the neutralizer circulate and mix with the chlorine and water. Be sure to check the pH and levels of the other chemicals in the hot tub afterward too, as altering the chlorine levels can impact them.

2. Dilute The Chlorine

Siphon the water or grab a bucket and throw some of the overly chlorinated water out of the hot tub. Then replace it with some fresh water. 

How much water should you remove? It depends on how high your chlorine levels are. You could start with 10-15% of your water.

This is a cost-effective and natural way of diluting the water and lowering the chlorine level. Give the hot tub some time to circulate the fresh water around before checking the new levels. You can adjust as needed from there. You’ll also need to rebalance the pH level and other chemicals when you drain and dilute.

Alternatively, you could decide to drain the whole hot tub and fill it up with fresh water and the correct amount of chlorine, but this is time-consuming and costly to do.

3. Use Sunlight to Naturally Reduce Chlorine in Your Tub

If you have an outdoor hot tub and are not in a rush to use it, you can simply try leaving your hot tub uncovered and let it be. Allow the sun’s UV rays to react with the free chlorine and allow the gas to evaporate therefore reducing the chlorine levels.

It may take between a few hours to a couple of days to do, but it is the most natural way to reduce the chlorine levels in your hot tub with minimal effort. It is a cost-effective way too! But, it is not guaranteed to always work.

When you have re-tested the chlorine levels, and they have dropped down to around 2 ppm you can then carefully add more chlorine to the hot tub to reach optimum levels. 

4 Ways To Prevent High Chlorine in Your Hot Tub

Adding granular chlorine to hot tub
Adding granular chlorine to pool

Preventing high chlorine levels is about controlling how much chlorine you put in. My tips are to:

  1. Test your water 2-3 times per week
  2. Use an accurate test kit
  3. Calculate and measure the chlorine amount carefully (you need to accurately know your hot tub’s water volume to do this)
  4. Reduce the use of chlorine floaters

3 Alternatives to Chlorine

Here’s a brief rundown on a few alternatives to chlorine. 

1. Use Bromine

If you want to eliminate chlorine altogether, you could switch to bromine.

Placing a bromine tablet in a bromine floater is a great way to sanitize your hot tub. Not only is it a less harsh chemical, but it is also more stable at hot temperatures. It is odourless and great for those with sensitive skin. It is recommended to keep the levels between 4 and 5 ppm in a hot tub.

2. Use An Ozone Generator

An ozone generator is not used solely on its own, but with chemicals such as chlorine or bromine to keep the hot tub clean and healthy, but you won’t need as much. The gas produced by the ozone generator in the circulation system sanitizes the pool water as it passes through the system.

Using an ozone generator with chemicals instead of solely relying on chlorine provides a much lower risk of causing harm to humans. However, it is super important to install it correctly.

3. Use a Mineral System

A hot tub mineral system containing silver and copper can greatly assist chemicals such as chlorine to do their job. They look like floating sticks or can be fixed into a cartridge system and release minerals as water passes through. 

A mineral system is another great option to reduce the amount of chlorine required in your hot tub whilst keeping it clean and safe to be in.

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