Pool filter elements

Activated filter glass is ideal when silica sand loses its retention capacity due to clogging and wear from continuous friction. Standard sand retains particles between 40 and 50 microns, while glass reduces this threshold to 15 or 20 microns without compacting into calcareous blocks.

When replacing the media, use 15% to 20% less weight than the manufacturer’s sand recommendation to avoid overpressure in tanks such as the Starpool Ø400 mm pool sand filter Ø400 mm without pump, with multiport valve. This reduces backwashing cycles and saves cleaning water throughout the 2026 season.

Replacement intervals depend exclusively on the physical properties of the material in the tank:

• Silica sand needs to be replaced every 3 to 5 years due to its edges becoming rounded and the buildup of bacterial biofilm.
• Filter glass retains its mechanical properties for 8 to 10 years thanks to its non-porous surface, which prevents biological sedimentation.
• Polyester fabric cartridges should be replaced every 1 or 2 seasons and require pressure washing with water every 15 days.

Monitoring the pressure gauge is essential to detect irreversible media saturation before overloading the motor.

Substrate being discharged into the bottom of the pool indicates a break in the lower laterals or an unsuitable filter media particle size. If the grains used are smaller than 0.4 millimeters, they will pass through the calibrated slots in the collectors, even if the distribution arms are in perfect working order.

To fix this issue, empty the filtration tank, inspect each collector arm for cracks, and refill the bed using the particle size recommended by the equipment manufacturer.

The main difference lies in the material’s microscopic structure and its effectiveness against colloidal dirt:

• Retention: glass captures dirt from 15 microns, while silica sand only retains particles from 40 microns.
• Bulk density: glass is 15% less dense, requiring fewer kilograms to fill the same internal volume.
• Cleaning: backwashing with glass uses up to 25% less water and requires half the pumping time.
• Channeling: silica sand tends to compact and create preferred water paths, a problem that does not occur with recycled glass.

In compact filtration systems such as the Star 300 sand filter with pump, glass significantly improves the overall performance of the recirculation system.

A 450 mm diameter filter typically requires 60 kg of silica sand or 48 kg of active filter glass. This ratio follows the rule of reducing mass by 20% when using calibrated glass media for hydraulic use in residential pools.

For high-flow equipment such as the Starpool Ø450 mm sand filter for pools with pump and selector valve, it is advisable to place a bottom layer of coarse 1 to 2 mm granules over the laterals and fill the rest with fine 0.4 to 0.8 mm granules. This layering protects the lower collectors from premature mechanical blockages.

The primary indicator of clogging is the pressure gauge located on top of the tank or on the control selector valve. When the pressure exceeds the initial operating pressure marked with a clean filter by 0.3 to 0.5 bar, it means the media has accumulated the maximum volume of debris it can hold.

Other direct symptoms include weak flow from the return jets and cloudy water in the pool. Backwashing for 3 minutes, followed by a 60-second rinse, restores operating pressure levels without disturbing the filter media.

Adding too much filter media fills the expansion chamber and causes particles to leak directly toward the distributor valve’s seals. During backwashing, the bed needs 30% to 40% of the tank’s total height free to expand without reaching the dome.

If the level exceeds this limit, the substrate will enter the selector valve body, eroding the seals of components such as the 6-Way Selector Valve 1½" (SP0710X62E). Strictly follow the fill marks engraved on the inside wall of the tank before closing it.