Filtersorb CT


Revolutionary Scale Prevention Media


The combination of FILTERSORB® SP3 and FILTERSORB SPA is an excellent choice for all residential, industrial, and commercial applications since it provides optimum scale prevention. The FILTERSORB® CT as a combined technology results in very high efficiency and provides additional capacity to the system.

The FILTERSORB® SP3 and FILTERSORB® SPA (Fig. 1) combination is well suited to treat water with hardness over 15 grains or permanent hardness over 250 mg of (Ca + Mg + SiO2 + SO4) is typically over 60 % of the total anions.

FILTERSORB CT removal solution
1. All ionic scale prevention (SPA & SP3 combination)
2. Carbonate Scales
3. Silica & Sulfate Scales (Silica & Sulfate Scales)

FILTERSORB CT Features (Fig. 2)

  • FILTERSORB SPA and SP3 Combined Treatment
  • All ionic materials are transformed into harmless crystals through catalytic processes
  • Prevents scaling and prevents organic pollution
  • Provides the healthiest water without the input of sodium and phosphate
  • Very easy to install
  • Cost reduction is very high compared to existing water softener.
  • No backwash and no regeneration required
  • No need for power connection, control valve, drainage
  • No maintenance required. No additional maintenance costs
  • No chemicals needed for disinfection
  • No change in TDS and pH
  • There is no sodium increase in the water (no salt needed)


Working Principle

Scale Prevention

High Efficacy

Water Softener

100 % Efficiency

Combined Treatment

Nucleation Assisted Crystallization

FILTERSORB® CT is a Nucleation and Exothermic Combination
FILTERSORB®CT is the best way to treat both anions as well as cations in hard water which can provide safe treatment of scale with 100 times more power.

FILTERSORB® SP3 works in a process of nucleation in which the media absorbs cations from its surroundings in the form of crystal and release CO2 in the form of gas → splitting a gas molecule.

FILTERSORB® SPA is an exothermic process in which the media separates the anions (negatively charged) from positively charged cations in the form of ionic bonds on the surface called EXO (outside) on very strong positively charged beads.

Anions in Hard potable water
Scaling including corrosion and biofouling are all related to each other. See figure on the left.
The precipitation of permanent hardness can only be inhibited by carbonate.
No corrosion can take place if the alkalinity of water is 8 to 8.5.

Anion Scale Prevention in Hard water

The two types of FILTERSORB® units are SP3 scale prevention and SPA anion scale prevention.

    • SP3 units prevent cationic scale based on positively charged ions such as calcium and magnesium and with nucleation it changes them into CaCO3 crystals.
    • SPA units prevent scale based on negatively charged ions such as sulfates, silicates and phosphates (Calcium phosphate).
    • FILTERSORB® CT: Mixed media. FILTERSORB® CT units prevent scale of both cations and anions, both positively and negatively charged ions. Watch-Water® recommends a mix of 50 % SP3 media and 50 % SPA media.
    • The FILTERSORB® systems do not need any regeneration, no chemical feed and no electrical valve head or waste water outlet. FILTERSORB® CT is a continuous up-flow system.
    • FILTERSORB® CT systems can treat both: Point-of-entry (POE) and Point-of-use (POU).

These systems will reduce the scale of calcium, magnesium, sulfates, silicates including phosphates.

Treatment of Cations and Anions Total hardness
Due to differences between temporary hardness and permanent hardness that make up the total hardness in water, we have combined FILTERSORB® SP3 and FILTERSORB® SPA in a 50 : 50 mix. This configuration is described as FILTERSORB® CT. The 50 % SP3 was selected to treat for temporary hardness based on carbonate hardness and the 50 % SPA was selected to treat for permanent hardness which is mostly based on sulfates and silicates.

FILTERSORB® SPA is only available as a combined product with FILTERSORB® SP3 (i.e. as part of FILTERSORB® CT) and cannot be supplied separately.