How to Neutralize Chlorine in a Pool

Chlorine is arguably the most important chemical in a pool, as it is used to provide a safe and clean swimming environment. However, it is possible to have too much chlorine if you’re not careful, which can result in a multitude of issues ranging from skin irritation and allergies to raising the pH in the water to hazardous levels.

Because of these reasons, it is essential to understand how you can neutralize chlorine in a pool to create the right level, which is what I’ll be discussing with you today.

There are three common methods to neutralize chlorine or lower chlorine levels in a swimming pool. These are; dilution, using a chlorine neutralizer, and time and sunlight. Chlorine neutralizers and dilution of the pool water will take a few hours to lower the chlorine levels, whilst using the sun can take several days.

Many methods can neutralize the chlorine in a pool, but the goal is to keep the chlorine level at about 1 ppm and 5 ppm for residential pools. Chlorine neutralizers, diluting the chlorine, and leaving it in the sun all help with the neutralization process.

Ways to neutralize chlorine in a pool:

  • Chlorine neutralizers
  • Diluting the chlorine in the water
  • Leave chlorine out in the sun
Swimming pool: how to neutralize chlorine.

What are Considered High Chlorine Levels in a Pool?

It’s important to understand the safe levels of chlorine in the pool so that you don’t go and spend unnecessary time and money.

The exact concentration of chlorine in your pool depends on the size and use of the pool, but the consensus is that the chlorine and pH level should be no more than 5 ppm and 7.6 respectively. Therefore, if you ever measure these parameters and see something beyond these numbers, you should not swim in your pool. And you may consider neutralizing the chlorine.

To achieve this in a pool, you should aim to either reduce the amount of chlorine (via sunlight exposure or neutralizers) or increase the amount of water in the pool to dilute the chlorine.

We’ll cover this in more detail further on in the article.

Are High Chlorine Levels Bad?

Although slightly higher chlorine levels are not too worrisome, having an excess of chlorine in your pool can create a variety of problems for your health and the environment. Some common symptoms you may experience when having an overly chlorinated pool include:

  • Skin irritation (appears as a rash or red bumps)
  • Eye irritation and appearance of blood-vessels
  • Respiratory illness due to inhalation of chlorine that’s on the surface of the pool (only after long-term exposure; typically clears up after a few days without treatment)

Though rare, over chlorination can cause chlorine poisoning, the symptoms of which can include nausea, vomiting, dizziness, wheezing, or coughing.

Can You Swim with High Chlorine Levels?

Whether you can swim in your pool or not depends on how chlorinated your pool is. If it is only slightly above the recommended standard (1-5 ppm; pH of 7.6), it might be okay in the short term. However, if it is highly chlorinated above the standard levels, I would highly discourage you from taking a swim.

It’s always better to take some time to make sure you’re swimming in a safe environment than to take any sort of health risk.

How to Tell If You Need to Neutralize Chlorine in Your Pool?

Of course, you’ll only know if you’ll need to neutralize chlorine in your pool if you measure its amount first.

The best and proven way to measure the amount of chlorine in your pool is using a DPD testing kit.

A DPD testing kit, or drop kit, measures both the free and combined chlorine levels to give you a total chlorine count in your pool.

Here’s how it works:

  1. Measure out a small amount of pool water
  2. Add buffered DPD powder to the water; the water will turn pink
  3. Add a FAS compound to the water one drop at a time until the water turns clear
  4. Each drop of the FAS compound is equal to 0.2 ppm of chlorine
  5. Multiply 0.2 with the number of drops you used to get the total amount of chlorine in your pool

Once you have the final number, you’ll be able to determine if you need to take steps in neutralizing the chlorine in your pool.

Pro Tip: DPD test kits are much more accurate than test strips.

Taylor Test Kit

TAYLOR TECHNOLOGIES INC K-2006 TEST KIT COMP CHLORINE FAS-DPD

5 Ways to Neutralize Chlorine in a Pool

1. Using Chlorine Neutralizers to Reduce Chlorine

Why Use Chlorine Neutralizers

Chlorine neutralizers are chemicals that are used to immediately lower the amount of free chlorine and sometimes combined chlorine (known as chloramines) in the water.

Because chlorine neutralizers can change the pH slightly and too much can strip all the chlorine from the water, it’s essential to put in the recommended amount as labeled on the product(s).

There are several kinds of these neutralizers, each having its respective pros and cons. We’ll take a look at these in more detail as well as how they work.

Popular Chlorine Neutralizers on the Market

Product NameUsageProsCons
Pool Dechlorinator Sodium Thiosulfate Pentahydrate 5 lbs  Add the appropriate teaspoon amount of product depending on the amount of water in your pool (1 oz per 10,000 gallons (37,854 L) of water). Wait for a few hours to a day for the water to clear.Effective at removing both chlorine and bromine.

Can be used in pools, aquariums, hot tubs.
Sometimes can take longer for water to clear.
BioGuard Chem Out – 2 lbsAdd the appropriate amount of powder to the water depending on the amount of water. (4 oz per 10,000 gallons (37,854 L) of water will remove 3 ppm of chlorine). Wait a few hours for the water to clear.Effective at removing both chlorine and bromine.

Effective at removing metal stains.

Fast dissolving.
The powder can get messy with use.

Not as effective in particular situations.

Pool Dechlorinator Sodium Thiosulfate Pentahydrate 5 lbs by Cesco Solutions - Premium Chlorine Neutralizer for Pools, Aquarium, Pond - Technical-Grade Chlorine Remover for Hot Tubs - Bulk Package

BioGuard Chem Out - 2 Lb (1)

How to Use Chlorine Neutralizers in General

  1. Determine the amount of water inside your pool.
  2. Add one cup of the neutralizer for every 5,000 gallons (18,927 L) of water.
  3. This will break down to about one ounce of neutralizer for every 100 gallons (379 L).
  4. A Low-pressure or high-pressure pump should be turned on to create turbulence in the water.
  5. The turbulence will help with the mixing of the neutralizer in the water.

2. Diluting the Chlorine to Reduce its Concentration

Neutralizing chlorine by dilution is another way to reduce high chlorine levels in a pool.

This involves partially draining the pool, then adding freshwater (otherwise known as a water change). There are several pros and cons for this method, which I’ve listed in the following table.

ProsCons
This is a good option if you are unable to get your hands on a decent chlorine neutralizer.The draining and refilling process can be very time-consuming. (You can reduce this time by backwashing using sand or DE filter).
This is a good option if you have blocked sand filters that you need to clear up (backwashing) or have high dissolved solids or metals in your water.This process can also end up being costly depending on your local water rates.
 This will also change things such as the temperature and pH of your pool as well as other chemicals levels, so it’s important to monitor these after diluting.
Diluting chlorine in pool pros/cons.

Another thing to note is that while using only water to dilute the chlorine instead of buying neutralizers can save you money, the costs of using all that extra water and having to add other chemicals such as pH increasers or stabilizers can add up rather quickly.

Therefore, in the end, it’s up to you to balance the pros and cons and see if this option is for you based on your situation.

3. Leaving the Chlorine Out in the Sun

Another method of neutralizing chlorine that your wallet will surely thank you for is to simply leave the pool under sunlight. This works because the UV rays in the sunlight convert chlorine into chlorine gas, which is then released into the atmosphere.

How Long Will the Chlorine Take to Dissipate or Lower?

It depends on your stabilizer (CYA) levels and the amount of organics in the water as well as other environmental factors. The more stabilizer in the water the longer it will take to burn off. And the more organics in the water, the faster the chlorine will reduce.

If your stabilizer levels are zero, that is, there is no stabilizer in the water, the chlorine will neutralize/dissipate in a matter of hours.

However, if you have CYA levels of around 50 ppm, it may take a few days for the chlorine to break down and get down to lower levels.

Some pros and cons of this method are listed as the following:

ProsCons
Doesn’t require extra effort i.e. trip to the store to buy a neutralizer, draining waterSlower than using a chemical neutralizer. And without careful monitoring during the process, chlorine levels can easily drop below what is needed.
Requires no monetary contributionUsing cyanuric acid, as part of stabilized chlorine, for example, can reduce the effectiveness of this method as it acts as a stabilizer to help chlorine last longer under sunlight.

4. Heating the Pool Water to Use Up the Chlorine

If you have a pool that is already heated, you can also consider heating the pool water a little further as a potential way of neutralizing the chlorine. Unlike previous methods, this one removes chlorine indirectly by creating an increase in bacteria due to the higher water temperature.

As the bacteria increase, more chlorine will be needed to kill them, reducing chlorine levels.

Considering you already have a heated pool, simply raise the temperature to around 90°F, about 10°F above the recommended level, for a little while. Monitor the chlorine levels throughout this time to ensure it does not dip below safe levels.

5. Using Hydrogen Peroxide to Produce Water and Oxygen

If you don’t happen to have a chlorine neutralizer on hand, another product you can consider using to remove excess chlorine is hydrogen peroxide. Hydrogen peroxide reacts with chlorine to produce water and oxygen. Therefore, if you can see oxygen bubbles coming from the pool, you’ll know the product’s working.

There are special hydrogen peroxide products made specifically for pools, which are more concentrated than those you might use to clean your home. Like the other methods I’ve mentioned earlier, just be sure to monitor your pool carefully to ensure the pH and chlorine levels don’t dip below the recommended standard.

Final Thoughts

In this article, we’ve taken a look at why you may want to neutralize the chlorine in your pool, as well as the methods of doing so. Here’s a summary of what we’ve discussed:

  • The overall safe amount of chlorine in your pool should be at around 3 ppm and a pH of 7.6, though the exact level will depend on your pool.
  • Having a highly chlorinated pool can carry several health risks.
  • There are several ways of removing chlorine from your pool depending on your situation and preference.
  • Regardless of which neutralizing method you choose, remember to always monitor the chlorine and pH levels in your pool to ensure a safe and clean swimming environment.

Neutralizing chlorine shouldn’t be much of an issue, therefore never ignore the fact that your pool might be overly chlorinated. You’ll be doing everyone a favor in the long run.

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