Natural flocculant for pools: an alternative for people with multiple chemical sensitivities
This article explains, from an informative perspective, what multiple chemical sensitivity is, why conventional pool maintenance products can be particularly problematic for people who suffer from it, and what natural alternatives exist. It does not constitute medical advice or replace the guidance of a healthcare professional.
Enjoying the pool with multiple chemical sensitivity: a challenge with a solution
For most people, summer and the pool go hand in hand. However, for those suffering from multiple chemical sensitivity (MCS), that moment of enjoyment can become a source of symptoms that force them to stay away from the water. Conventional maintenance products, particularly the aluminum sulfate present in most flocculants on the market, are precisely the type of compounds that can trigger the most reactions in these individuals.
Fortunately, alternatives exist. In this article, we explore what MCS is, why certain chemical compounds in pool water are especially problematic, and how natural flocculant can help create an aquatic environment that is more respectful of the health of those living with this condition.
What is multiple chemical sensitivity?
Multiple chemical sensitivity (MCS) is a chronic condition officially recognized in Spain as a disease in 2015, characterized by the appearance of recurrent and reproducible symptoms in multiple organs and systems after exposure to levels of chemical substances that most of the population tolerates without problems. These symptoms disappear or improve when exposure to the triggering agent is eliminated.
Although the exact mechanisms of MCS are still the subject of scientific research, there is broad consensus that it is an altered response of the autonomic nervous system to certain synthetic or metal-based chemical compounds. Consequently, the main management strategy is to reduce the chemical load in the affected person's environment.
Most frequent symptoms after chemical exposure
- Neurological: headache, brain fog, difficulty concentrating, dizziness, and intense fatigue after exposure.
- Respiratory: mucous membrane irritation, shortness of breath, dry cough, and a feeling of chest tightness.
- Cutaneous: itching, redness, hives, eczema, or burning sensation on the skin after contact with the triggering agent.
- Digestive: nausea, abdominal discomfort, and altered bowel transit in some cases.
- Ocular: tearing, eye itching, redness, and a burning sensation.
According to estimates from patient associations, between 0.5% and 3% of the Spanish population may suffer from some degree of multiple chemical sensitivity. In 2015, the Ministry of Health included it in the classification of diseases of the national health system under the CIE-10 T78.4 code, which represented a formal recognition of its existence as a medical condition.
However, diagnosis remains complex, and many affected people live for years with their symptoms without receiving a definitive diagnosis, which makes it difficult to adopt appropriate preventive measures in their daily environment.
Why pool water can be problematic in MCS
Conventional pool water is not just water. It is a complex aqueous solution where the main disinfectant (usually chlorine), its reaction by-products (chloramines, trihalomethanes), auxiliary maintenance products (pH adjusters, flocculants, algaecides), and organic waste from bathers coexist. For a person with MCS, this mixture can represent a significant exposure load.
The most problematic compounds in pool water
| Compound | Origin in the pool | Why it can be problematic in MCS |
|---|---|---|
| Chloramines | Reaction of chlorine with organic matter | Irritants to respiratory mucous membranes and skin; responsible for the "pool smell" |
| Aluminum sulfate | Conventional flocculants | Dissolved aluminum can be absorbed through the skin; it has been associated with neurological alterations in chronic exposure |
| Trihalomethanes (THM) | By-products of chlorine with organic matter | Volatile compounds inhaled during bathing; some with documented toxic potential |
| Muriatic acid | Conventional pH adjuster | Concentrated hydrochloric acid; residues in the water can irritate respiratory tracts and sensitive skin |
| Quaternary ammonium algaecides | Algae treatment | Surfactants that remain in the water and can trigger skin and respiratory reactions |
| Puerto Verde Natural Flocculant | Natural alternative to aluminum sulfate | No metals or synthetic compounds; biodegradable; does not generate accumulating residues in the water |
Of all the auxiliary products commonly used in pool maintenance, aluminum sulfate present in conventional flocculants is possibly the most easily replaceable with a natural alternative without losing effectiveness. Unlike chlorine, which fulfills an essential disinfecting function, flocculant only has a clarifying function that can also be performed with polymers of natural origin.
For a person with MCS, this substitution represents a direct and significant reduction in the chemical load of bathing water, without needing to modify the main disinfection system or forgo the sanitary safety of the pool.
Aluminum in pool water: what the available evidence says
Aluminum sulfate has been used for decades in both drinking water treatment and pool flocculants, and at usual doses, it is approved by European health authorities. However, from the perspective of MCS, it is worth analyzing in more detail what happens to this aluminum once dissolved in bathing water.
Dermal absorption of aluminum and chemical sensitivity
Human skin acts as a selective but not impermeable barrier. Various studies have documented that aluminum ions can penetrate the skin barrier under conditions of prolonged exposure. This occurs especially when the skin is warm and hydrated, as happens during swimming. In people with healthy skin, this absorption is minimal, but in people with compromised skin barrier or MCS, the situation may be different.
Furthermore, aluminum dissolved in the water is also partially inhaled through steam during bathing. Therefore, it represents an additional exposure pathway especially relevant for people with respiratory symptoms associated with MCS.
The Ministry of Health of Spain recognized multiple chemical sensitivity as a disease in 2015, including it in the classification of diseases of the national health system. Since then, the Ministry's own consensus document states that reducing exposure to chemical agents is the main therapeutic strategy for affected people.
You can consult the official information on the Ministry of Health's multiple chemical sensitivity page →
Why the precautionary principle is relevant in MCS
In the context of MCS, the precautionary principle takes on special importance. There is not yet an aluminum tolerance threshold established specifically for these individuals. In addition, substitution with a natural flocculant is completely viable without losing effectiveness. Therefore, choosing the metal-free alternative is the most prudent option from an environmental health perspective.
In the management of MCS, the concept of "total load" is fundamental. Each source of chemical exposure, even if individually small, contributes to an accumulated threshold. When that threshold is exceeded, symptoms appear. Therefore, the most effective strategy is not to eliminate a single source, but to simultaneously reduce all possible ones.
Replacing conventional flocculant with a natural one is one such possible reduction. It does not eliminate the entire chemical load from the pool, but it does eliminate a specific source of metallic compounds that can be easily avoided without significant additional cost.
Natural flocculant as an alternative: what makes it different
Same result, without metallic compounds
Puerto Verde's natural flocculant performs the same function as conventional aluminum sulfate flocculant: it groups suspended particles that are too fine for the filter and forms larger flocs that can be retained or vacuumed from the bottom. The difference is in how it achieves this.
Instead of using a metallic salt, it uses naturally sourced components that act by attracting electrical charges. Water particles have a negative charge, and the natural polymers in the flocculant have a positive charge. Therefore, they attract and group together spontaneously without needing any metal catalyst. The result is identical in effectiveness, but without introducing aluminum into the water.
Characteristics specifically relevant for people with MCS
- No aluminum sulfate or metallic compounds: completely eliminates this source of exposure to dissolved aluminum in bathing water.
- No synthetic surfactants: does not introduce artificial surfactants into the water, which are another group of compounds frequently problematic in MCS.
- No perfumes or fragrances: formulated without any aromatic compounds, which are among the most frequent triggers in people with chemical sensitivity.
- 100% biodegradable: degrades completely in water without generating accumulative by-products or persistent residues.
- Does not alter pH: by not modifying the acid-base balance of the water, it does not require the addition of additional corrective products that would add chemical load to the environment.
- Spanish manufacturing with full traceability: allows exact knowledge of the composition and origin of all ingredients, which is especially valuable for people with MCS who need to precisely control their chemical environment.
Reducing the chemical load of the pool: an integral approach
Replacing the flocculant is an important step. However, it should be understood as part of a broader strategy to reduce the chemical load of the water. Below we explain the complementary measures that can most contribute to creating a more tolerable aquatic environment for people with MCS:
Maintain stable pH and alkalinity with natural products
When water pH fluctuates, chloramine concentration increases significantly. Chloramines are one of the most irritating compounds in pool water. Therefore, maintaining pH between 7.2 and 7.4 with a natural pH increaser and alkalinity between 80 and 120 ppm with a natural alkalinity increaser directly reduces the formation of chlorine by-products and, consequently, the total chemical load of the water.
Additionally, by working with optimized water chemistry, less chlorine is needed to maintain disinfection, which also helps reduce the concentration of trihalomethanes and chloramines in the water and in the immediate air around the pool.
Efficient filtration: the first line of defense
- Correct filtration (8-12 hours daily in summer) eliminates much of the organic matter before it reacts with chlorine, thus reducing chloramine formation at the source.
- Keeping the filter clean through regular backwashing improves its efficiency and reduces the chemical load that reaches the disinfectant.
- Combining efficient filtration with natural flocculant ensures that the water is as free as possible of suspended particles, minimizing the demand for all treatment products.
Other habits that reduce the chemical load of water
- Pre-swim shower: pre-swim showers for all bathers drastically reduce organic waste entering the water and, consequently, chloramine formation.
- Covering the pool when not in use: reduces the entry of dust, organic matter, and external organisms that consume chlorine and generate by-products.
- Bathing schedule: the concentration of volatile trihalomethanes is higher when the water is very hot. Bathing during cooler hours of the day can reduce inhalation exposure.
- Environment ventilation: in indoor pools or poorly ventilated terraces, ensuring good air circulation reduces the concentration of volatile compounds in the immediate environment.
What natural flocculant cannot do
Informative honesty is especially important when discussing health. Therefore, it is necessary to be clear about the limits of what a natural flocculant can and cannot provide in the context of MCS:
What it does achieve
- Completely eliminate aluminum and metallic compounds from the flocculation process.
- Reduce a specific source of chemical load in pool water.
- Keep the water crystal clear with the same effectiveness as conventional flocculant.
- Not alter pH or require additional corrections that add more products to the water.
What it cannot achieve on its own
- Eliminate chloramines or trihalomethanes formed by the reaction of chlorine with organic matter.
- Replace disinfection: chlorine or another disinfectant system is still necessary to ensure the sanitary safety of the water.
- Guarantee the absence of symptoms in people with MCS, since each case is different and tolerance thresholds vary enormously from person to person.
Multiple chemical sensitivity manifests very differently in each person. Some people with MCS tolerate a pool with optimized natural maintenance well. Others, however, may react even to residual chlorine or other unavoidable compounds in treated water. Therefore, any decision about pool use in the context of MCS should be made individually and, when possible, with the support of a healthcare professional familiar with this condition.
This article is for informational and educational purposes only: to offer information about the most respectful options available for those seeking to reduce the chemical load in their aquatic environment.
Frequently asked questions about natural flocculant and multiple chemical sensitivity
Below we answer the most common questions about the use of natural flocculant in the context of multiple chemical sensitivity:
What is the difference between natural and conventional flocculant for a person with MCS?
The main difference is the absence of aluminum sulfate in natural flocculant. Aluminum sulfate introduces aluminum ions into the water that can be absorbed through the skin during bathing, which in people with MCS can be a source of exposure to a metal that many of them do not tolerate well. Natural flocculant achieves the same clarifying result through plant-based components, without introducing any metallic compounds into the water.
Does natural flocculant completely eliminate risks for people with MCS?
No. Natural flocculant eliminates a specific source of chemical load (the aluminum from conventional flocculant), but pool water treated with chlorine still contains other compounds like chloramines and trihalomethanes that can be problematic for some people with MCS. Its use should be understood as a partial reduction measure of the chemical load, not as a total solution. In any case, each person with MCS has a different sensitivity profile and must evaluate their tolerance individually.
What other pool products should a person with MCS review?
Beyond flocculant, the products that introduce the most chemical load into the water are algaecides (especially quaternary ammonium compounds), conventional pH adjusters (muriatic acid), and high-concentration trichlor tablets. Replacing pH and alkalinity adjusters with natural alternatives, such as those offered by Puerto Verde, helps significantly reduce the overall chemical load of the water. In any case, consulting the doctor who manages the MCS case is always the most advisable step before making changes to the environment.
How is natural flocculant used and how long does it take to act?
Puerto Verde's natural flocculant comes in an easy-to-dose powder format: 2 scoops per 10 m³ of water. With the recirculation pump running, spread it slowly around the entire perimeter of the pool. After keeping recirculation active for 2 hours, turn off the pump and let the water rest for 8 to 12 hours. The next day, vacuum the bottom with the pool cleaner and the water will regain its transparency. It does not alter the pH nor does it require additional corrections.
Is there any certification or guarantee of the composition of the natural flocculant?
Puerto Verde's natural flocculant is manufactured in Spain with complete traceability of the production process and without additives, preservatives, or synthetic compounds. Spanish manufacturing with process control ensures that the declared composition is the real one, something especially valuable for people with MCS who need to know exactly what compounds are present in their environment. If you need detailed information about the exact composition of the product for your specific case, you can contact Puerto Verde directly before making the purchase.
Where can I buy Puerto Verde's natural flocculant?
You can find it in the natural flocculant section of our online store puertoverde.es, with shipping throughout Spain and in different formats depending on the size of your pool. It is also available on Amazon with Prime shipping if you prefer that option. If you have doubts about whether the product is suitable for your specific MCS situation, we recommend consulting your doctor before use.
🌿 Less chemicals in your pool, more peace of mind for your summer
Natural flocculant · No aluminum sulfate · No metallic compounds · Spanish manufacturing · Shipping throughout Spain
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