Go Back

Of course, the water in your swimming pool is the main element that needs to be maintained at high standards to ensure the well-being and enjoyment of the users. However, the choice of types of pool water and associated maintenance (cleaning and disinfection treatments) is not always so straightforward.

This article will cover:

  • Each type of pool water and our recommendations to best care for your pool;
  • A few special cases: ponds, biopools, lakes, and lagoons.
Key types of pool water

From the “standard” in pool water – chlorine – to saltwater and others, pool operators can choose to treat their pools with different types of chemicals or solutions to ensure the best results. Here are the main options to choose from.


Chlorine is the so-called “gold standard” of pool water types, known for its efficiency at killing bacteria. It counteracts contaminants in the water such as sweat, dirt, urine, and sunscreen or body lotions through a chemical reaction. Chlorine can be added once per week, using liquid, tablets or granular chlorine. Due to its ability to act like a residual sanitizer, chlorine can effectively sanitize the pool for a long time after it’s been added to the water.

However, one of the major drawbacks of a chlorine-based water system is that it requires active maintenance since chlorine doesn’t react too well to certain substances. For example, when mixed with bacteria in the pool, it creates a substance known as “chloramine”, which produces that particular chlorinated pool smell.

Moreover, when chlorine interacts with contaminants in the pool, it can cause asthma, red eyes, dry skin, lifeguard lung, lung irritation and other health issues. Finally, when handling chlorine, pool operators must keep in mind that it is a chemical, so it needs to be stored and handled carefully .


Saltwater pools are less common but are definitely a worthy alternative to chlorine. Instead of it, you would add salt to the water, which interacts with a special generator known as a salt chlorinator. And this creates chlorine through electrolysis .

This option significantly reduces work requirements for pool operators, while still being efficient at killing bacteria and having residual disinfectant power, as chlorine. Another advantage is the lack of chemicals being used. It’s worth mentioning that, while saltwater generally requires less maintenance than chlorine, it requires a higher investment to set up.

One of the main drawbacks with a saltwater system is that it can corrode pool equipment much faster than chlorine. However, there is a way to slow this down by using a sacrificial anode made of zinc, which gives off more of its own ions faster and causes the salt to attack it first, wearing through this anode instead of the other metallic objects in the pool.


Mineral pools’ popularity is increasing for several reasons, including their health benefits. A mineral pool system is intended for residential and small pools . It contains high concentrations of magnesium, which has beneficial effects on the skin: with a mineral pool, skin will remain silky, in stark contrast to chlorine or saltwater systems which dry skin and hair.

Overall, mineral pools offer a better water quality than other alternatives, avoiding itchy skin, dry eyes and other side effects that bathers could endure with the more chemical water alternatives.


UV systems work by flowing pool water over a UV lamp that breaks down bacterial DNA as the water passes over it. They offer additional pool water sanitation along with chlorine or other chemicals by destroying chlorine-resistant microbes and other contaminants while reducing chemical consumption.

Keeping them from reproducing, UV systems sterilize bacteria within the water. But this doesn’t mean bacterial cells can’t make their way back into the pool. A major downside of this type of pool water is that UV systems only sanitise and disinfect, but do not oxygenate the water. Unlike chlorine, the UV system disinfects but does not give disinfectant power to the water. When it passes through the UV system, it is disinfected, but water on itself does not disinfect.

Neolysis - Combining UV and salt electrolysis

It is possible to combine the UV technique with low salinity electrolysis, creating an excellent solution for the treatment and disinfection of swimming pool water. Such an example is the Neolysis system, one of the most natural and sustainable technologies in the market for water treatment. Other systems can use Neolysis as its main tool such as Freepool2.

Neolysis combines UV water treatment with salt electrolysis in a single reactor that delivers disinfected and chlorinated water. Pool water that is treated using Neolysis is totally natural. It provides great efficiency and many benefits. Avoids to add salt or chlorinated products, provide water and energy savings and improves bathing conditions.

It decreases the incidence of respiratory issues, ocular and nasal complications or itchy eyes. The process is also beneficial to the environment by reducing gas emissions from facilities without affecting water quality.


Finally, ozone systems work by injecting ozone gas (O3) into the pool plumbing to oxygenate pool water contaminants and chlorine-resistant microbes. They generate electrical energy that breaks down oxygen molecules (O2) to create a chemical reaction that produces ozone.

Ozone pool systems allow pool operators to reduce chlorine consumption and are stronger oxidizers than chlorine. Similarly to saltwater systems, ozone systems can make pool water feel “softer”.

But, as a toxic gas, ozone can accumulate in pool pump rooms and under pool covers, and therefore requires the use of degassing vessels, ozone destructive chambers or other complex systems in order to function safely and properly. Ozone gas can also be corrosive to rubber gaskets, covers and other pool equipment, depreciating your pool investment.

Other types of aquatic solutions

Beyond swimming pools, aquatic solutions like biopools or lakes and lagoons feature, by their design, different types of pool water and cleaning systems.

Ponds and biopools

Naturalised ponds and pools offer an authentic environment with a wide variety of flora and fauna, beautifying indoor and outdoor spaces. These water features use natural filtration and water disinfection treatments.

They require less use of chemicals to influence the balance of the water, so there is a much lower environmental impact from these treatments. In fact, by featuring one of these water solutions, you will be totally reducing chlorine and diluting your acid usage.

Additionally, there is a natural water treatment based on bacteria called “Microbe-Lift Clean & Clear”, with a living bacteria formula that speeds up the natural removal of organic waste. Being completely natural, this solution even allows animals to live in or drink the water. The bacteria will remove organic waste into CO2, biomass and water, thus highly increasing the water quality.

Although naturalised pools and ponds are meant to offer an experience that is as close to nature as possible, creating a unique decor or even allowing swimming in almost-natural pools, they cannot be left untreated and unkept. This is why we advise using various natural filtration systems to ensure your water feature is in optimal condition.

For public swimming pools, bio pools are not accepted in all countries. So, operators must consult the regulations according to each territory.

Lakes and lagoons

Artificial lakes are a trendy ornamental aquatic solution that provides a luxurious touch to an indoor or outdoor installation, and can include water shows and fountains. Although not suitable for swimming, the artificial lakes allow boating and surfing.

Lagoons , on the other hand, are artificial structures that seek to recreate a coastal environment . This innovative solution enhances outdoor leisure spaces and can host a variety of activities and services including bathing, which diversifies the reasons to spend time in a resort.

It is rather convenient to know the difference between freshwater lagoons and saltwater lagoons . While the water in the former can be treated like in a conventional swimming pool, with filters, pumps, etc, saltwater lagoons use water from the sea, which is transported through tanks and buried pipes.

For sea water, the pH is usually between 7.5 and 8.4, above the usual levels for freshwater (around 7.0). That is the reason why chlorine dioxide (CLO2) needs to be used in gaseous format, as it is the most effective when working with high pH levels.

Freshwater lagoons can ideally have a flocculation system to absorb any small residue through the suction wells, as well as an ultraviolet system that reduces the smell of chlorine and the level of chloramines (<0.6 ppm) while disinfecting against microorganisms. All of this can be automated using smart control systems.

Understanding pool water types to optimise the cleanliness of your water

With the variety of options available for treating and disinfecting pool water, it is important to know the pros and cons of each type of pool water in order to make the best choice for your project.

Beyond swimming pools, water treatment of ponds, biopools, lakes and lagoons should also be taken into account . For they use the right systems that are gentle enough for the environment, while also being particularly effective.

Pools for schools: an ideal educational space to train and promote the values of sport
Swimming pools create important athletic, social, and…
A connected, smart, responsible and modern pool
We live in an increasingly connected world,…
Freepool2 – An innovative technical solution
Fluidra presents a water treatment solution that…
Flocculation and coagulation in water treatment: key to water transparency
The removal of small particles represents a…