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Pool maintenance without chlorine – is it possible? Many pool owners do indeed equate pool chemistry with the use of chlorine tablets.

However, today there are already ways to replace chlorine. The reason for these new developments are, firstly, people who suffer from chlorine allergy, and secondly, the swimming experience with chlorine is not ideal. Irritations and the familiar smell of chlorine on clothing bother even the biggest water rats.

We have taken a look at the numerous alternatives to chlorine in the pool and give you a brief overview of how a pool without chlorine is possible.

Why chemical pool cleaning is important

All sorts of different contaminants collect in a pool. Leaves, twigs, sand and dirt are the start, but bacteria, pathogens, algae and insects are also a big problem. If you neglect pool maintenance for too long, your private swimming paradise will become a home for all kinds of uninvited guests.

Chemical pool cleaning is your defense against all these foreign organisms. You use disinfecting chemicals to kill off the foreign bodies and ensure that the water in your pool remains clear and safe for your health.

Chemical cleaning is mostly done with chlorine that is added to the water either in the form of stabilized chlorine, which stays in the water for a long time, or as non-stabilized chlorine, which decays quickly (for example, during shock chlorination). Signs that chemical pool cleaning is needed to include a slippery floor or pool walls, algae growth, or cloudy water.

The advantages and disadvantages of chlorine in pools.

Chlorine is the most commonly used disinfectant. I guess it’s human nature to just keep doing a lot of things with a long history, even when better options are already available. Is the same true with chlorine? If so, which alternatives are better?

First, let’s take a quick look at the pros and cons of chlorine as a swimming pool sanitizer. Chlorine is an effective oxidant that has a strong germicidal effect, this is at the same time a problem as it can cause skin irritation on sensitive skin. The mucous membranes and eyes are also severely affected.

By the way, the supposed “chlorine smell” does not come from the chlorine itself, but is caused by chloramines, which are formed when chlorine and foreign bodies combine. The odor is unavoidable in large, public pools, but your private pool need not smell as unpleasant. In fact, with a thoroughly performed shock chlorination, the chloramines are destroyed and the odor disappears.

Alternatives for chlorine

There are already a number of alternatives to chlorine on the market today, but which are any good? Which solutions really do not require chlorine? Does pool maintenance without chlorine work at all? And which method is least harmful to the environment?

Active oxygen

Active oxygen or hydrogen peroxide is another chemical product for water treatment. The agent is available in tablet, granule and liquid form. In combination with a UV system, active oxygen is one of the best ways to eliminate the need for chlorine in pool cleaning.

The effect of the oxidant hydrogen peroxide is further enhanced under the ultraviolet light. The hydroxyl radicals released effectively kill germs and bacteria of all kinds. When reacting with foreign particles, the substance decomposes into hydrogen and oxygen – both harmless substances.

The active oxygen is sensitive to high water temperatures. If you rely on active oxygen, water temperature should be below 25°C. In addition, foam-free algaecide or flocculant should be added to supplement treatment with active oxygen. Some manufacturers offer granules or tablets with active oxygen, which already contain the necessary additives.

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Bromine is the one more alternative to chlorine that we want to introduce. In the periodic table, bromine is just one place away from chlorine and chemically the substance is also very similar. It is a solid disinfectant for pools and to some extent reduces the dependence on chlorine.

While bromine is a disinfectant, it is less good than chlorine when it comes to oxidation. Water disinfected with bromine is not cleaned as well as with chlorine. For this reason, a hybrid system with bromine and chlorine is the common practice.

For you, this means not completely removing chlorine from your repertoire, but at least reducing your use of the chemical. Bromine is better for warmer temperatures than chlorine, which evaporates quickly. So for pool owners in warmer climates, bromine is the chemical of choice.

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PHBM is the abbreviation for polyhexamethylene biguanide (yes – we didn’t know that by heart either). The drug is often abbreviated as biguanide and in stores it is available under the name Baquacil.

The most important thing you need to know about PHMB or Baquacil is that this chemical molecule is completely chlorine-free. Accordingly, no unpleasant byproducts such as chloramines are produced when using this disinfectant.

Treating a pool with biguanide is time-saving because biguanide only needs to be added weekly. The chemical compound does not irritate the skin or eyes. The agent also does not attack the lining of the swimming pool. So, unlike chlorine, biguanide does not have to be dissolved before it can be added to the pool.

Furthermore, the chemical structure of PHMB is extremely resistant to UV radiation, flexible in terms of pH and largely resistant to temperature changes. Because of these properties, PHBM ensures constant control of bacteria in pool water.

However, biguanide is not an oxidizing agent. Consequently, it cannot break down many organic contaminants, such as urine, sweat and some algae. Another disadvantage is that biguanide is not compatible with bromine, copper and chlorine. Therefore, normal shock chlorination is not possible.

In practice, hydrogen peroxide will be used as an oxidizing agent. For the control of algae, PHMB relies on a separate algicide.

Ozone generators

You have probably already heard about the ozone layer. Ozone filters dangerous radiation from the sun. Ozone generators put ozone gas into the pool water. The gas reacts with impurities and in this way purifies the water.

There are two different types of ozone generators:

  • Ultraviolet light: UV ozone systems are the most common. In this system, UV lights are installed as part of the water treatment system. The UV light kills contaminants in the water.
  • Corona discharge: ozone generators that use corona treatment use an electric arc to kill pathogens.

Ozone generators are systems that are completely chlorine-free. The only drawbacks are that they are expensive to set up and are less effective in humid climates.

Salt Water Electrolysis

Instead of adding chlorine to the pool water, a pool with salt water electrolysis system only needs swimming pool salt. The added salt is broken down to produce inorganic active chlorine.

The advantage is in addition to the low operating costs for salt, electricity and water. The advantage of salt water electrolysis is that it always produces chlorine as needed and, due to the fact that the chlorine is not first stored temporarily, has a stronger effect.

However, saltwater electrolysis is not a truly chlorine-free solution, as chlorine is the product of this process. The difference with a classic pool is that salt is added instead of chlorine. The salt content in a pool with salt electrolysis is about 0.3 to 0.5%.

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As you can see, it doesn’t always have to be chlorine. There are numerous alternatives. A pool without chlorine is within the feasible range. Depending on the particular method, the mode of action sometimes resembles more and sometimes less chlorine.

However, we would like to point out again that when using the disinfectants presented, you must follow the instructions provided by the manufacturer. Use the information on the packaging as a guide to determine the correct dosage.

Regardless of whether the pool is chlorine-free or chlorinated, the main thing is to keep the pool clean and to ensure that swimming is safe for your health. Part of your pool care should also include regular shock chlorination to really kill off any foreign matter.

There is always a bit of a learning curve when using new procedures. However, with a little experience, each of these is quickly mastered, and you can take a carefree dip in your pool.

Larry has been a true water rat since childhood. Pure pleasure turned into a passion. That's why he is the first point of contact for friends and acquaintances when it comes to pool-related problems. He is an integral part of the PoolHandbook editorial team.