Gravity systems, such as the Pure Filters equipped with Coldstream FTO+ cartridges, do not remove mineral salts for several reasons

Selectivity of filter materials : Coldstream cartridges use a combination of ceramic and high-quality activated carbon. These materials are designed to specifically target contaminants such as bacteria, viruses, parasites, chemicals, and heavy metals, while allowing beneficial minerals like calcium and magnesium to pass through. These minerals are essential for human health and their presence in water is generally desired.

Ceramic pore size : Coldstream's ceramic-based filters have pores small enough to block microbiological and chemical contaminants, but large enough to allow dissolved minerals to pass through. The dissolved mineral salts are much smaller than the organic and inorganic contaminants targeted by the filters.

Adsorption filtration method : Activated carbon works by adsorption, a method where contaminants bind to the surface of the activated carbon. However, dissolved mineral salts do not bind in the same way, allowing these minerals to pass through the filter.

Purpose of Filtration : The primary goal of Coldstream filtration is to make water safe to drink by removing harmful contaminants while retaining minerals that are beneficial to health. Removing minerals could make water less palatable and potentially less beneficial to health.

In summary, Coldstream filters are designed to target hazardous contaminants while preserving beneficial mineral salts. This ensures pure, healthy and drinkable water without stripping away essential nutrients.

So Pure Filters gravity filters don't remove all limescale?

Exactly, gravity filters like Pure Filters equipped with Coldstream FTO+ cartridges will not remove all the limescale from the water. Here's why:

Nature of Dissolved Minerals : Limestone is composed mainly of calcium carbonate and magnesium carbonate, which are minerals dissolved in water. These minerals are much smaller than the organic and inorganic contaminants that Coldstream filters target.

Pore Size : The pores of Coldstream ceramic filters are designed to block larger particles, such as bacteria, viruses, and other contaminants. However, the dissolved calcium and magnesium ions (which make up limestone) are small enough to pass through these pores.

Filtration Purpose : The primary purpose of Coldstream filters is to remove harmful contaminants while preserving health-promoting minerals. Calcium and magnesium, while they can contribute to water hardness (limestone), are also essential minerals for the human body.

Filtration Method : The activated carbon used in Coldstream filters works by adsorption, capturing contaminants on the surface of the carbon. Dissolved minerals, such as calcium and magnesium, do not bind in the same way and pass through the filter.

In summary, while Coldstream filters improve water quality by removing many dangerous contaminants, they are not designed to remove limescale (dissolved minerals) from water.

To reduce water hardness, specific treatment methods, such as water softeners, would be required.