While the external appearance of gravity water filters is often similar, their performance primarily depends on the nature of the filtering materials and the physicochemical mechanisms they employ.
This page focuses on the composition of Ultimate Star Filter® water filters and on how their materials interact with water during filtration. The objective is to understand what actually occurs at the microscopic level, independently of the system’s overall design.
The apparent effectiveness of a filter may conceal very different mechanisms at the microscopic scale.
The following sections detail the main materials that make up the filtration matrix.
Activated carbon is the primary filtration material for dissolved organic compounds, chlorine, and many by-products resulting from water disinfection. In most gravity-fed systems, it forms the core of the chemical treatment of contaminants.
Derived from carefully selected carbon-based materials, it is thermally activated to create an extremely dense network of micro- and nanopores. This structure gives the material a considerable internal surface area — ranging from several hundred to over a thousand square meters per gram.
Molecules present in the water bind to this surface through a physicochemical phenomenon known as adsorption, which differs from simple mechanical filtration. Unlike a sieve that retains visible particles, adsorption enables the capture of dissolved and invisible substances, attracted to and retained on the material’s surface through molecular interactions.
The activated carbons used are NSF®-certified and selected for:
This material therefore acts primarily on dissolved and invisible contaminants, while allowing the naturally occurring minerals in the water to pass through.
In addition to activated carbon, a nanofiltration membrane introduces two distinct mechanisms: physical retention and electro-adsorption.
On the one hand, its extremely fine pores help block certain particles, colloids, and microorganisms that would not be fully retained by adsorption alone.
On the other hand, the membrane technology is based on a principle of electro-adsorption: electrostatic charges present on the surface of the media attract and retain submicron particles, pathogens, trace pharmaceutical residues, and cellular debris, even when their size is smaller than the apparent pore size.
This mechanism enables effective filtration with low pressure drop, compatible with gravity-fed operation, and a potentially higher flow rate than purely mechanical filters of comparable fineness.
Unlike pressurized systems, this membrane is designed to operate in gravity filtration, which implies a controlled balance between retention capacity, flow rate, and long-term stability.
Certain dissolved metallic contaminants — such as lead, arsenic, or other trace metals — are not effectively retained by activated carbon alone. Their capture requires specific physicochemical mechanisms adapted to their ionic form and behavior in solution.
Dedicated filtration media are therefore integrated to improve the selective retention of these elements. Unlike the relatively non-specific adsorption of activated carbon, these materials are designed to interact in a targeted manner with certain dissolved metallic species.
They act primarily through:
Integrated at the core of the filtration matrix, these media operate in complement to activated carbon: the carbon primarily treats organic compounds and chlorine, while the specialized media targets dissolved metallic contaminants.
These materials are also NSF®-certified for use in drinking water, confirming their safety and compliance with health requirements applicable to water treatment devices.
The filtration materials are treated to limit bacterial growth inside the cartridge.
This action is described as bacteriostatic: it prevents the multiplication of microorganisms without disinfecting the water itself.
The objective is to preserve the sanitary integrity of the filter during its use.
Filtration relies on several complementary phenomena:
It is the combination of these mechanisms that helps improve the quality of the filtered water.
Despite their effectiveness, these technologies have inherent limitations related to activated carbon filtration:
Filtered water therefore retains elements such as calcium and magnesium.
The performance of a filter does not depend on a single material, but on the system as a whole:
Certification covering the complete system provides additional assurance compared to tests performed on a single material alone.
The components used in Ultimate Star Filter® filters meet recognized international standards and are subject to independent evaluations:
These data make it possible to assess filtration capabilities and document performance on measurable and verifiable grounds.
Understanding the technology and composition of a filter makes it possible to look beyond appearances and assess its actual reliability. In a field where external differences are minimal, internal architecture and the quality of materials are the true indicators of seriousness.
This technical transparency is part of a precautionary and responsible approach: providing improved water quality without compromising safety or long-term performance stability.
To Explore the Filter Technology Further
Key points to remember:
Explore in detail:
FAQ - Technology & Composition
No. It primarily acts on organic compounds and chlorine, without removing essential dissolved minerals.
Each material targets different contaminants. Their combination enables more comprehensive filtration.
No. It works in complement, providing an additional physical barrier.
It improves water quality but does not constitute a system of complete sterilization.
The reduction of chlorine and certain organic compounds may improve taste, while preserving the natural mineral content.
