Hyperionised water: filtration, filter media compatibility and detailed physical & chemical explanations
Hyperionised water has a hyperionic state, i.e. a specific physical & chemical equilibrium involving the distribution of dissolved ions, their electrostatic interactions, their solvation (ion-water molecule interaction) and electrochemical parameters (redox/ORP potential, ionic activities, etc.).
This state can be altered when water is circulated through filtration systems designed for “conventional” water, as some filter media do more than simply retain particles: they adsorb, exchange or reconfigure ions at the solid/water interface. In this case, the filter becomes a chemical actor capable of neutralising the hyperionic state.
A filter can do more than “filter”: certain materials interact with the water and can gradually diminish its properties.
1) The key principle: the hyperionic state is sensitive to solid interfaces
1.1 Water is not "the same" near a surface: the electric double layer
When water comes into contact with a solid, an electric double layer (EDL) is formed:
- a layer of ions “bound” to the surface (Stern layer),
- a diffuse layer where ions are distributed according to electrical potential.
This arrangement depends on the water’s ionic strength, defined by:
where ci is the molar concentration of ion i and zi is its charge.
The typical “size” of the electrostatic interfacial region is the Debye length:
- εr: relative permittivity of water
- ε0: permittivity of free space
- kB: Boltzmann constant
- T: temperature (K)
- NA: Avogadro’s constant
- e: elementary charge
- I: ionic strength
Interpretation: the more ionised the water (high I), the smaller λD: the interfacial effects are highly localised but very intense.
On contact with a material, water rearranges itself into a thin "electrical" layer.
The more ions the water contains (e.g. seawater), the greater these effects.
1.2 Electrochemical potential: why ionic balance can be "shifted" by a medium
The behaviour of an ion in water is governed by its electrochemical potential:
- μi: electrochemical potential
- μi0: reference
- R: ideal gas constant
- ai: activity of ion i
- F: Faraday constant
- ψ: local electrical potential
The activity is:
(γi: activity coefficient, ci: concentration)
Crucial point: close to a surface, ψ ≠ 0 and the ion distribution changes. If a medium filters, adsorbs or exchanges ions, then ci, γi and therefore ai change. This shifts the balance that supports the hyperionic state.
Certain materials "attract" or "capture" ions: this changes the water's internal balance, rather like removing ingredients from a recipe.
2) Why silica-based media (sand/glass/diatomite) are incompatible
2.1 Silica and glass: same surface chemistry (silanol groups)
Filter sand (quartz), filter glass beads, diatomite and many related “mineral” media share surfaces rich in silanol groups:
These groups ionise according to pH:
When the surface carries ≡SiO-, it becomes negative and attracts cations:
- monovalent: Na+, K+
- divalent: Ca2+, Mg2+
- ionic accumulation at the interface,
- partial trapping or specific adsorption,
- changes in local activities,
- rearrangement of the interfacial water layer (hydrogen bonding and solvation).
Sand and glass are not neutral: their surfaces carry charges that attract ions and modify the water passing through.
2.2 The "total surface area" effect: why a sand filter rapidly neutralises hyperionic water
A filter bed (sand or glass) combines:
- a large specific surface area (aggregates),
- high contact time (deep bed),
- repeated passes (pool/spa recirculation).
Even if the interaction “per cm²” is low, the total effect becomes dominant, as the number of interfacial sites is enormous.
Interfacial capture can be represented by simplified adsorption kinetics (schematic):
- q: adsorbed quantity
- C: solution concentration
- θ: fraction of occupied sites
- ka, kd: adsorption/desorption constants
If the total surface area is large, the filter’s effective capacity to “rearrange/capture” increases sharply.
The more surface area in contact (fine sand, large filter, continuous circulation), the more the water is "reconditioned" by the medium... and the more its properties diminish.
2.3 Diatomite: an aggravating example
- more active interfaces,
- accelerated capture/rearrangement effects.
Diatomite is highly porous, further amplifying interactions with water, making it particularly unfavourable.
3) Zeolites: ion exchange ("chemical" media, not just filter media)
3.1 Typical exchange reactions
Schematic examples:
- ionic composition (cations),
- ionic strength I,
- activities ai,
- balances associated with the hyperionic state.
A zeolite acts like an "ion sponge": it transforms water chemistry by exchanging ions.
4) Activated carbon: massive adsorption + electrochemical impacts (ORP)
4.1 Adsorption: why it upsets the balance
Activated carbon has a very high specific surface area and adsorbs a large number of dissolved species.
Two classic models:
Langmuir:
Freundlich:
- q: mass adsorbed by carbon mass
- C: solution concentration
- K, KF, n: constants
Adsorption removes dissolved species and shifts the solution balances.
For a hyperionic state that depends on an ionic/solvation equilibrium,
it is structurally unfavourable.
Activated carbon is designed to "suck out" what is dissolved. However, to preserve a particular state of the water, you need to avoid a material that constantly removes elements.
4.2 ORP / redox: Nernst relationship
The redox potential follows (for a given pair):
- E: measured potential
- E0: standard potential
- n: number of electrons exchanged
- Q: reaction quotient
Carbon surfaces can promote certain surface reactions (adsorption + electron transfer), locally modifying Q and therefore E.
A medium can also influence the "oxidising/reducing" balance of the water: this can contribute to destabilising the desired state.
5) Golden rule: "the more chemically efficient, the more incompatible".
A “high chemical performance” filter medium (adsorption, ion exchange, active surface, microporosity) is not neutral. Hyperionised water needs a hydraulic and filtering environment that filters without reintroducing chemicals.
Filters that modify water the most (carbon, zeolite, silica) are precisely those to be avoided.
6) Compatible media: neutral mechanical filtration
6.1 PP/PE polymers (polypropylene/polyethylene)
- relatively neutral surface,
- no structural ion exchange,
- no massive adsorption,
- interception/screening filtration.
Polymer cartridges retain particles without "capturing" ions: they preserve water better.
6.2 Cellulose (cotton/paper/fibers)
- effective on particles,
- chemical interactions are generally weak compared with active mineral media.
Fibre filters act like a "fine sieve" and better respect the balance of the water.
6.3 Stainless steel strainers
Mechanical filtration media:
- high-performance water purification,
- no chemical interaction.
Stainless steel strainers are perfectly compatible with Sublio technology.
7) Practical recommendations (pool, spa, thalassotherapy facility, seawater)
- Pools / spas: prefer stainless steel strainers, PP/PE cartridges and/or cellulose fibrous media.
- Seawater: extra care, as high ionic strength → stronger interfacial interactions.
- Sanitary water / networks: aim for stability + neutrality, strictly avoid mechanically active media.
The more salt-laden the water (seawater), the more "neutral" filtration is required.