What Pool Chlorine Level is Too High? FAQs Answered

By Blue Cube on Thursday, 25th May 2023 in Tips & Tricks.

Chlorine is an essential part of maintaining a safe and hygienic swimming pool; however, consistently elevated chlorine levels can create hazardous conditions for swimmers.

With that in mind, this article will help you answer your top questions about pool chlorine levels, such as “What is the ideal pool chlorine level?”, and the risks associated with high chlorine levels in a pool, including “What pool chlorine level is too high?”, and “Is it safe to swim in a pool with high chlorine?”

We’ll also look at alternatives to chlorine for pool sanitization, how to test for high chlorine levels, and what you could do to lower high chlorine levels. 

From the potential health risks associated with high chlorine levels to the optimal range of free chlorine in a pool, this article has everything you need to know about pool chloride levels.

Let’s dive right in!

Short Summary

  • It is essential to regulate chlorine levels in a pool between 1-3 ppm, as levels exceeding 5 ppm can be hazardous.
  • Swimming in a pool with high chlorine levels should be avoided.
  • The highest safe chlorine level for a pool is 3 ppm.
  • A DPD testing kit can help you test your pool for high chlorine levels.
  • Blue Horizons Chlorine Reducer can be used to help you reduce chlorine levels in your pool.

What is the Ideal Pool Chlorine Level?

The ideal chlorine level for a pool is between 1-3 parts per million (ppm.)

Maintaining your swimming pool effectively means maintaining proper chlorine levels. This is essential for keeping them clean and safe for swimming.

To minimize potential reactions to chlorine in a pool, swimmers should protect their eyes from exposure and rinse off any remaining chlorine after swimming. If there is a strong chlorine odour present in the pool, it may be necessary to decrease the chlorine concentration. 

This will help eliminate the chlorinates that are responsible for the smell.

What swimming pool chlorine level is too high?

With the above data in mind, it’s important to understand that chlorine levels too high can be dangerous. 

The maximum safe chlorine level is 3 parts per million (ppm). Anything above 5ppm is considered a hazard and should be addressed immediately.

If you find numbers as high as 7-10ppm, the pool should not be used until chlorine levels return to safer levels. As we’ll cover below, there are a number of risks associated with high chlorine levels, so it’s best not to risk it if your chlorine levels are that high.

Not sure if your chlorine level is too high? Speak to a pool expert for some free advice today.

What are the Risks of Too Much Chlorine in Pool Water?

Elevated chlorine levels in a pool can be a significant health risk, with skin rash, eye irritation, respiratory difficulties, and even chlorine poisoning being possible side effects. Exposure to chlorine can also lead to skin sensitivity or even an increased risk of developing asthma due to lung irritation.

In addition to the health risks, having an elevated chlorine concentration in use with pool equipment, swimwear, and towels can lead to their deterioration. This is because chlorine is a powerful oxidizing agent, meaning it can break down the fibres in these items.

To ensure a healthy pool, proper hygiene must be adhered to. Otherwise, the buildup of bacteria and other contaminants can lead to an unhealthy environment, even if the chlorine levels are within the ideal range.

What Causes Excess Chlorine Levels in a Pool?

There are several reasons why this could be happening. Firstly how much chlorine has been added to the pool? What is the chlorine level? Sometimes too much chlorine can be added by accident, it can be common if your pool is green and you think you need to shock it, etc. 

However, sometimes high levels of cyanuric acid can cause chlorine lock and therefore it will not kill off algae but you go ahead and add more chlorine anyway. Try to avoid this.

High chlorine levels can also be caused by using too much liquid chlorine or chlorine tablets, not using a chlorine stabilizer, or having an improperly maintained pool.

How Can I Test for High Chlorine Levels in My Pool?

We can not stress this enough but test, test, test, your pool water! It is essential for keeping a healthy pool. Make sure your test strips are in date, or invest in a good chemical test kit or photometer as it will ultimately save you a lot of hassle in the long run.

A DPD testing kit is a tool that can be used to measure the amount of free and combined chlorine in your pool water. It utilizes diethyl-p-phenylenediamine, which is a chemical that reacts with free and combined chlorine to produce a colour.

To assess high chlorine levels with a DPD testing kit, fill the test tube with pool water, add the DPD reagent or tablets, and then compare the colour of the water to the colour chart provided with the kit. If you’re using a photometer the handheld machine will read the reagent’s water reaction with a test tub and tell you the precise reading. 

If the colour is darker than the highest level on the chart, do not use the pool and backwash immediately. Then test again when the chlorine level has dropped, due to the freshwater being added.

Do I Need an Expert Pool Water Treatment?

While maintaining your own pool water may seem like a straightforward solution, it’s often best left to the experts.

Efficient pool water treatment and ensuring correct chemical dosing is vital not only for safety but also for water clarity. Blue Cube Pools offer an expert pool water treatment that will help you to keep your pool water in perfect condition year-round.

The service required will depend on the type of equipment being used, for example, whether it is residential or commercial, an outdoor or indoor pool or a pool or spa, but our pool professionals can advise on the best approach for your pool.

How Do I Lower High Chlorine Levels in a Pool?

Exposure to sunlight can effectively reduce the level of chlorine, so you can try letting it dissipate by leaving your pool cover off. Alternatively, diluting the pool through partial draining and replenishing it with fresh water is often an effective solution.

If these methods are not effective in lowering the chlorine levels in the pool, pool chemicals like sodium thiosulfate and hydrogen peroxide-based neutralizers and other chlorine reducers can be used. Remember, it is essential to adhere to all manufacturer instructions when using these products.

Blue Horizons Chlorine Reducer is a popular product used to lower bromine or chlorine levels in pool water after shock treatment procedures or as a problem solver if the pool has been accidentally ‘overdosed’ with chlorine or bromine.

How to apply Blue Horizons Chlorine Reducer:

Blue Horizons Chlorine Reducer - Blue Cube Pools
  1. Pre-dissolve the product in a clean plastic container at a maximum rate of 100g of product per 2.2 gallons (10lts) of clean warm water. Stir well to ensure the product is fully dissolved. Carefully add the resulting solution to the pool whilst the pump(s) are turned “on”, preferably near the water inlets to aid distribution.
  2. If applying after shock treatment, allow a minimum of 8 hours for shock chlorination to oxidise bather wastes from the water before application.
  3. Measure the free chlorine/total bromine level in the water, then using the dosing table below, calculate the total amount required.
  4. Split this total amount into 4 smaller doses. Apply each smaller dose, allowing time to thoroughly circulate (2-3 hours for commercial pools/6-8 hours for domestic pools) before retesting chlorine/bromine level and if necessary adding further doses.

Closing Thoughts

Elevated levels of chlorine in a pool can be a health hazard, and the optimal range of free chlorine in a pool is 1 to 3 ppm. In this article, we discussed the risks of high chlorine levels in a pool, what causes them, how to test for them, and how to lower them.

At Blue Cube Pools, we provide pool water treatments, pool maintenance and repairs, and swimming pool installations to keep your pool at its best. Our pool equipment shop also provides all the maintenance and sanitisation supplies you need to keep your pool clean and safe.

Contact us for more information or shop our pool chemicals and dosing tools today!

Pool Owners FAQs, Answered

Is chlorine level 7 too high? Is 5 too high for chlorine in the pool?

Yes, chlorine levels that are higher than 3 ppm can be hazardous. It is important to adjust the chlorine level of your pool as soon as possible if levels are as high as 5-7 ppm.

Is it safe to swim in a pool with high chlorine?

No, it is not safe to swim in a pool with high chlorine levels as it can cause skin and eye irritation, amongst other risks. As such it is important to adjust the chlorine level of your pool or contact a pool maintenance expert as soon as possible if levels are too high.

What happens if pool chlorine is too high?

If the chlorine levels in a pool are too high, it can cause skin and eye irritation, as well as damage to hair and swimwear. It also increases the risk of asthma episodes for those with respiratory sensitivities. Additionally, chlorine that is too high can result in an unpleasant odour.