How to Lower The Chlorine Level in Your Pool

Written by Michael Dean
November 28, 2023

chlorine tablet in a swimming pool

Chlorine is the most important chemical in a pool to keep the water clean and safe. So, checking your pool chlorine levels often is important to ensure they are balanced. However, it’s possible to have too much of a good thing. If there is too much chlorine in your pool, you will have to lower it to ensure the safety of swimmers.

Read on to learn how to lower chlorine levels in your pool and what causes high chlorine levels.

Main Takeaways

  • Chlorine can be balanced by slightly draining and refilling the pool, allowing the pool to be exposed to the sun for an extended time, or using a chlorine neutralizer.
  • Chlorine can easily be over-added to pool water by adding too much shock, not being exposed to sunlight, or having improperly balanced cyanuric acid levels.
  • High chlorine levels can affect swimmers’ respiratory systems, cause skin irritation, and damage pool equipment.

How to Tell If Your Pool’s Chlorine Level Is High

The rumor that you can smell the amount of chlorine is a myth. But you can certainly tell if your pool is over-chlorinated by feeling the effects on your body through irritated eyes and skin. Thankfully, there are safer and faster ways to check the amount of chlorine in a pool.

Use a pool water testing kit! For example, you could use an OTO (Orthotolidine) kit to measure the amount of free chlorine in your pool. Alternatively, you can use a DPD (Diethyl Phenylenediamine) test kit to estimate the total amount of chlorine in your pool, including the free chlorine and chloramines, to get a more accurate read.

Another easy way to test your chlorine levels is using a chlorine test strip. These strips are very easy to use! Simply dip a strip into the water for a few seconds, shake it off, and compare the color to your color chart.

How to Lower Chlorine Levels In Your Pool Fast

Depending on the pool’s chlorine level, you can use different methods to lower it. Below are the seven most effective ways to reduce the chlorine level in your pool to get in that 3 ppm sweet spot.

1. Use the Sun

Using sunlight is the easiest way to regulate chlorine levels in your pool. That said, it likely won’t do any good if chlorine levels are severely high. But the sun can be a great solution if the levels are only a little over the ideal limit.

If you have a pool cover, leave the pool uncovered for a couple of days, exposing the water to the sun.

The logic behind this is that ultraviolet (UV) light from the sun naturally breaks down chlorine, reducing the chlorine level in your pool to a safe level.


  • It’s free
  • No use of chemicals


  • It’s not practical for indoor pools
  • It may take a while

2. Throw A Pool Party

It may sound odd, but inviting your friends and family for a swim can be a great way to counteract above-normal chlorine levels. Just make sure to do this only if the chlorine level is slightly above normal. Otherwise, the high chlorine levels could harm your pool patrons.

So how does this work? Well, it’s all about taking advantage of chlorine’s primary purpose: sanitizing your pool water. Inviting people over will increase the number of contaminants and potentially reduce the pool’s chlorine level.


  • It’s free
  • No use of chemicals


  • Not practical if the level of chlorine in the pool is at extreme levels
  • Might irritate some of the swimmers

3. Drain and Dilute the Pool Water

Diluting your pool is an effective option if the chlorine level only needs to be reduced slightly.

To dilute your pool, you’ll have to drain some water from your pool and replace it with fresh water.

It’s important to test the water for all other chemical levels after doing this since you’ll be draining other chemicals alongside the chlorine.


  • It’s free
  • No use of chemicals


  • Increases your water bill
  • Rebalancing of other chemicals may be necessary afterward

4. Use Sodium Thiosulfate or Other Chlorine Neutralizers

Sodium thiosulfate balances the chlorine level in your pool and acts as a chlorine neutralizer. Different doses and treatments may be required depending on your pool’s chlorine level and capacity.

Besides sodium thiosulfate, you can use various chlorine neutralizers, such as sodium metabisulfite, sodium sulfite, or sodium bisulfite. By and large, sodium thiosulfate is the most commonly used.

When adding the chlorine neutralizer, it’s important to avoid adding too much.

Over-neutralizing the chlorine might lower the level to the point that it fails to fulfill its purpose of fighting contaminants.


  • Highly effective method
  • Cost-effective


  • Significantly lowers the pH of your pool
  • Results take time

5. Use Hydrogen Peroxide

Hydrogen peroxide is a pool chemical oxidizer that breaks down chlorine through a series of chemical reactions.

For best results, use hydrogen peroxide designed explicitly for pools. If you opt for everyday home cleaning products that contain small amounts of hydrogen peroxide, you may find that they are less effective.

Before using hydrogen peroxide, test the pool’s pH and ensure it’s higher than 7 for maximum effectiveness.


  • Cost-effective
  • Gives immediate results


  • Lowers your pool’s pH
  • Less effective if your pool’s pH is below 7

6. Use Ascorbic Acid

Using ascorbic acid (also known as vitamin C) is another means to reduce chlorine levels in your pool.

Most pool owners opt for this method to lower chlorine levels because the reaction between ascorbic acid and chlorine is fast, and the results are non-hazardous to humans.

However, ascorbic acid will decrease the pool’s pH when used in low-alkaline waters.


  • Effective in cases where chlorine levels are extreme and need to be significantly reduced
  • Chemicals used are non-hazardous


  • Costly depending on your pool’s size
  • Requires large doses to ensure effectiveness

7. Stop Adding Chlorine To The Pool

If your chlorine levels are too high, you definitely don’t want to add any more chlorine to your pool! Even if it is engrained into your pool maintenance routine, skip adding chlorine to avoid pushing the levels even higher. If you have a salt chlorine generator or an automated chlorine system, ensure that you turn them off while you sort out the high chlorine levels.

What Causes High Chlorine Levels?

The recommended chlorine level in a pool is 3 parts per million. At this level, the chlorine in your pool can keep the water sanitized without harming or irritating swimmers.

Several things could cause the chlorine level in your pool to exceed the recommended range of 3 parts per million.

The most common reason for this is pool owners accidentally adding too much chlorine to the water. If you shock the pool, you may have miscalculated the amount of chlorine to add. Or, if you are using chlorine tablets for your pool, you may have added one too many.

Chlorine naturally dissipates in sunlight. So, the chlorine breaks down when your pool water is exposed to UV rays.

If your pool is located indoors or under a covering, it will only get minimal sunlight, which means the chlorine won’t break down as fast as it would under direct sunlight. In some cases, this can be a good thing because you will save more money on chemicals and won’t have to top up your chlorine as often. But you’ll need to make sure you test the water before adding more chlorine because it is easier to add too much. This is also the case for areas with lots of tree cover or regions that do not get a lot of direct sunlight throughout the year.

And finally, an improperly balanced combination of cyanuric acid and chlorine can also cause a rise in the pool’s chlorine level. Cyanuric acid is a chemical used to protect the chemical structure of chlorine by reducing the rate at which it breaks down under the sun.

Risks of High Chlorine Levels

At the right level, chlorine is harmless to humans. However, unfortunately, it can pose health risks to anyone exposed to it at extreme levels.

Discoloring is the most common issue caused by a pool with high chlorine levels. This can lead to your bathing suit fading too fast. Since chlorine can damage colors, it can even affect recently dyed hair.

High chlorine can also cause more serious health issues if exposure is prolonged. Here are some common health issues caused by exposure to high levels of chlorine:

  • Respiratory illnesses such as asthma due to the excess chlorine vapor formed on the surface of the pool
  • Eye irritation and over-dilated blood vessels in the eyes, for those of you who prefer swimming without goggles
  • Dry skin and hair
  • Dizziness
  • Burning sensation in the eyes, nose, throat, and chest
  • Nausea and vomiting
  • Skin irritation characterized by a red rash with raised, itchy bumps

Typically, these symptoms of high chlorine levels clear up after a few days or weeks. Though rare, one extreme effect is chlorine poisoning, which usually requires immediate medical attention.

Besides health concerns, excess chlorine levels could eventually damage your pool equipment and pool cover.

Alternative Sanitation Methods For Lower Chlorine Levels

The above methods can lower your chlorine levels in a standard chlorine pool. However, you can also permanently reduce the amount of chlorine in your pool by switching to an alternative sanitation method. These include saltwater chlorinator pools, mineral pool systems, and natural pools.

Saltwater Chlorinator

Saltwater pools are becoming increasingly popular as they require fewer added chemicals and less maintenance. The salt cell in a saltwater chlorinator regulates the amount of chlorine in your pool, so it is much easier to ensure the pool’s chlorine levels are balanced. You don’t generally have to add chlorine to a saltwater pool, so it is unlikely the levels will get too high.

Mineral Pool System

Mineral pools are healthier alternatives to standard chlorine or saltwater pools. These pools use natural chemicals to sanitize the water and are much safer for swimmers. Mineral pools need MUCH less chlorine, only .5 PPM! So, the water is less likely to irritate the skin and eyes of swimmers. That being said, these pools are a task to maintain and should not be considered by average pool owners as they still require a lot of upkeep and expensive chemicals. While a chlorine-free pool seems like a dream, it is definitely a double-edged sword.

Natural Pool

Natural swimming pools are a unique type of pool that utilize plants to keep the water clean instead of chemicals. These pools still have a pump, but instead of a filter system and chemicals, it uses natural resources to clean the water. It may seem like a big risk to have a pool that doesn’t use chlorine or other chemicals to clean the water, but these pools can actually be safer than standard chlorine pools! Overall, these pools require less upkeep. However, you’ll still have to keep them clean and watch out for algae!

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

Something went wrong. Please check your entries and try again.

Wrapping Up

Now that you’ve seen the causes and impact of high chlorine levels, you’re one step closer to making your pool safer. Some of the best ways to lower the chlorine levels are to heat your pool, drain and dilute the water, or use another chemical like hydrogen peroxide to help mitigate the chlorine. I hope you find this information useful in helping you to keep your pool safe for your family and friends.

Have questions? Shoot me a message.

Scroll to Top