This filter consists of a tank made of plastic aggression treaty for the protection of the water in the pool.

In the sand filter, the filter material consists of silica sand in a single homogeneous layer, with a particle size between 0.4 and 0.8 mm. At the bottom may be a layer of larger particles with the function of protecting the system of support and facilitate the distribution. At the top is that a free volume expansion chamber to allow proper cleaning of the sand.

The filtering is done from the top to down through the layer of sand and water is distributed in the tank through a central distributor with a minimum of 6 to a maximum of 12 plugs.

The filtration quality depends on:

• layer height of the sand;

• filtration rate;

• holding capacity of sand.