Over the past years, new systems have been developed to resolve the disadvantages presented by the sand filtration systems. One of the developed solutions is the one that use perlite: this system guarantees an excellent filtration level (1/2 micron) and the use of a minimum quantity of energy and water. This system uses diatom instead of perlite, and it requires a minimal amount of space in the technical room.
The Defender filter proposed by Myrtha Pools uses perlite, a volcanic rock with a vitreous structure (like the obsidian stone). This rock is ground and exposed to heat-treatment to obtain a thin powder that adhere at the supports creating a stratum of filter material.
The perlite can filter particles as fine as a micrometer.
The diatomite is another media used in the pre-coat filters like the Defender. The diatomite is defined also as diatomaceous earth, a sedimentary siliceous rock with organic origin, mainly composed of fossilized diatom shells (a kind of algae).
The diatomite is characterized by white colour and elevated porosity. In this kind of filters the diatomite is used in form of thin powder, it adhere at the supports and constitute the filter material.
High level of filtration (even in presence of protozoans)
Existence on the market of filters that manage regeneration and pre-coat independently, simplifying the filter management
Saving backwash water (this means a saving of chemical reagents and energy too)
Minimal amount of space (a smaller technical room is required)