Sand Filters

Although in colloquial language we still talk about sand filters, this denomination is increasingly imprecise and limited. In reality, what we commonly call "filter" is a container tank of filtering material, and its function does not depend so much on the name as on the type of filtering load that it houses inside.

what is a pool filter?

A pool filter is an indispensable element of the purification system. It is a pressurized tank through which water from the pool circulates. Its mission is clear: to retain the particles of dirt in suspension or those that are extracted when passing the pool cleaner, returning the clean water to the pool.

Therefore, regardless of the type of load used, the objective is always the same: to improve water quality by removing suspended solids.

why is talking about "sand filters" no longer enough?

For many years, the most common material inside the filter was silica sand, which gave rise to its popular name. However, today there are other filter media options that surpass traditional sand in efficiency, both in particle holding capacity and in durability and sustainability.

By simply speaking of "sand filter", we are omitting a whole range of modern possibilities, such as filter glass (like AFM®): more efficient, with less need for backwashing and longer service life.

The filter is not a simple "sand filter". It is a key part of the purification system, and its performance will depend to a large extent on the type of filter load we incorporate. Knowing the available options and how they affect maintenance, water consumption and the final quality of the bath is essential to make the right decision.

why choose sand filters for your pool?

• High filtration efficiency for coarse and medium particles.
• Easy maintenance: only requires periodic backwashing.
• Durability: with the use of a good filter load, they can operate for many years with optimal results.
• Economical in the long term: low power consumption and low replacement costs.

They are an ideal choice for those who are looking for effective purification without technical complications.

how do sand filters work?

The filtering system is based on a tank filled with filtering material (silica sand, glass, zeolite, etc.). The dirty water enters through the upper part of the filter and passes through the filtering load, which retains the impurities. The clean water exits at the bottom and returns to the pool.

When the sand becomes saturated with dirt, a backwash is performed, which reverses the water flow and expels the accumulated impurities to the drain.

Main characteristics of sand filters

• Filtration capacity: between 20 and 50 microns, depending on the type of filter load.
• Filter size: must be adapted to the volume of the pool and the power of the pump.
• Type of selector valve: side or top, allows functions such as filtering, washing, rinsing, recirculating, emptying or closing.
• Filter media type: from silica sand to premium filter glass (AFM®).
• Body material: laminated polyester or injected plastic; the former is recommended for durability.

Buying Guide: What is the best sand filter for you?

Recommendations according to the type of user:

• Small pools (up to 20 m³): 400 or 500 mm diameter filters.
• Medium pools (30-40 m³): 500 or 600 mm filters.
• Large pools (40-65 m³): 600 mm filters.
• Very large pools (more than 65 m³ up to 130 m³): 750 mm filters.

These recommendations are intended for private pools and considering a water renewal time of about 4-5 hours.

Explanation of technical terms:

• Flow rate: volume of water that the filter can process per hour.
• Backwash: backwashing.
• Filter load: material that traps dirt (sand, zeolite or glass).
• Filtration rate: measured in m³/h/m², it influences the efficiency and wear of the filter media.