Stinging eyes and smelly water in swimming pools

Posted on Friday, 4 March 2022

If you have stinging or irritated eyes as a result of swimming pool water or smelly swimming pool water, you need to take a look at our professional tips to resolve these issues.

Stinging eyes in the swimming pool is a problem caused by an unbalanced pH level in the water. This condition is medically known as chemical conjunctivitis. 

According to Michel Hlavsa, the Centers for Disease Control and Prevention (CDC) chief of Healthy Swimming Program in the USA, this problem is also caused by chloramine, which is the result of the reaction between free chlorine particles with nitrogen and ammonia, produced by organic waste such as human excretion and secretion: sweat, urine, saliva, etc.

It can also be caused by excessive limescale, which due to the hardness of the water can cause eye irritations.

Healthy swimming pools should not have a strong smell of chlorine, because this means an excessive presence of chloramines which can be harmful, especially for our eyes. It can also be a sign that there is too much chlorine in the water. Each of these problems has to be dealt with differently. At CTX we will advise you on how to get a healthy and irritant free water in your pool.

Irritated eyes from swimming pool chlorine: solutions

Firstly, before doing anything, we need to analyse the various parameters in the water. Those which most interest us in terms of irritation are pH levels, alkalinity, chlorine levels, and limescale. 


At CTX we have a range of different instruments to analyse water. Analysis kits with reactive agents which, when coming into contact with water samples, provide us with immediate and quick results that are highly accurate and dependable. We also have analysis strips, with reactive agents that also measure other parameters. Additionally, there are other devices and systems, such as reactive agents, multifunctional photometers, and our CTX water analysis laboratories. 


The next step before dealing with the specific pH imbalance issue is to correct it by applying certain products to the swimming pool’s water. To do this, we will use specific pH regulators such as:

  • CTX-10 pH Minus (granulate) or CTX-15 pH Minus(liquid)-. pH reducer for reducing the pH to between 7.2 and 7.6 when it is above 7.6. It reduces the efficiency of disinfectants, and it is a very useful product that prevents water from irritating the eyes or mucus of swimmers.

  • CTX-20 pH Plus (granulate) or CTX-25 pH Plus (liquid). pH enhancer  for adjusting the pH to between 7.2 and 7.6 when it is below 7.2. Just as with other pH balancing products, it must be used when swimmers are not in the pool.

The total alkalinity of the water can also irritate eyes when it is excessively high, due to low alkalinity causes the pH to fluctuate a lot. Our company offers an alkalinity enhancer in powder, CTX-21 Alka+, ideal for all kinds of swimming pools. 


Another issue that can irritate swimmers’ eyes is chloramine. This needs to be dealt with by using a hyperchlorination treatment or shock chlorination. We should also use a quick dissolving dichloride, highly concentrated. CTX offers CTX-200/gr ClorShock, a dichloride in granules that is fast and effective for all types of swimming pools. It is commonly used in emergencies like this one, and for those pools, which have not been maintained or cared for and require recovery through the application of a highly effective and robust treatment. Whenever the water appears to be a bit cloudy, this initial hyperchlorination process needs to be implemented. Furthermore, this specific product does not change the pH levels of the water, which is very useful and highly valuable when balancing this out.

Finally, if the problem is the hardness of the water, meaning we need to resolve the levels of calcium and magnesium in the water, which can irritate eyes.

How to get rid of smelly pool water

A smelly pool is a very common problem, and the best way to deal with this is by knowing what the causes are. To do this, specialist measurement tools and chemical products need to be used for the best possible disinfection results. The first thing to take into account is that when we are talking about smelly pool water, this is generally caused by an excess of organic waste. But another one of the main causes of this unfortunate situation are the so-called chloramines. At CTX we provide you with advice on how to resolve these problems according to the specific conditions and requirements of your pool.


It is essential to frequently clean the bottom of our swimming pool, as that is where the organic waste tends to be. We also need to remove all of the floating waste with a net most days.


Solutions against smelly pool water

Chloramines are also one of the main causes of smelly pool water. Pools with excessive chloramines can also irritate our skin. Due to the irritation and smell they cause, there is only one way to deal with and resolve this specific problem. 


To do this, a series of processes are required, using specific instruments and products like those included in the CTX catalogue. 


Firstly, we need to analyse the different parameters of the water in our pool. We need to pay close attention to the chloramines which are formed by a combination of free chlorine molecules and different types of organic waste, this can include organic waste from around the pool such as leaves, insects, rain, etc. or algae, human secretion and excretion. 


The main factors to work out to resolve the problem of a smelly pool are the pH levels, alkalinity, chlorine levels, and limescale.


To analyse these parameters of the pool we need to use measurement tools such as those offered by CTX:

  • CTX analysis kits, which include a range of reactive products to mix with the water to give us accurate and reliable results. Some of these work by using colorimetry, which gives us equivalent numerical values in comparison to a previous colour scale interpretation.
  • We also have Pooltester Kits to determine the pH levels and disinfectant levels quickly, precisely, and simultaneously by using just a few water samples so that the reactive tablets included in the kits can react upon contact with the water.
  • We also have Checkit Kits, a compact and easy to use comparison tool that quickly provides measurement results by means of a chromatic scale.
  • CTX also offers Minikits, which are essentially quick tests based largely on titrimetric methods.
  • Among the CTX measurement systems, there are also analysis strips. For example, three or seven parameter free chlorine strips. 
  • We also have other systems and measurement systems, such as multifunctional photometers, all noted for their excellent accuracy and reliability.


The second and final step to remove bad smells is hyperchlorination or shock chlorination, which is fast acting. To do this we apply 15g of  CTX-200/GR ClorShock for every m3 of water. It is a highly concentrated dichloride in granules with 55% of effective chlorine. It is a product that you should always have to hand in case of emergencies or if your pool begins to smell bad.

CTX will advise you on how to choose and apply each tool and chemical compound required to resolve these issues. If you need anything, feel free to speak to us.