Sand or Silex
Whether you should use sand or silex in your filter can always be found on your filter or in the manual. The amount of sand or silex is also stated. This depends on the size of your sand filter. Always fill your filter properly with the filter medium recommended by the manufacturer.

Sand
When sand is recommended as a filter medium, it is very important to know what thickness the sand grain should have. The thickness can always be found on the filter or in the manual. Sand can be found in three different grains: 0,4 mm - 0,8 mm, 0,5 mm - 1 mm and 0,8 mm - 1,25 mm.
A too thick grain can cause your pool water not to be filtered optimally. A grain that is too thin can cause sand grains to end up in your pool.

Silex
Silex is a kind of pebble. Here too, it is important to check how much silex you need for your filter. This depends on the size of your filter. The thickness of your filter medium is also very important here. With silex, we have the following thicknesses: 1,7 mm - 2,5 mm, 2,0 mm - 3,15 mm, 3,15 mm - 5,6 mm and 5,0 mm - 8,0 mm.

Using both filter media
Sometimes it is also recommended to use a combination of both sand and silex in your filter. Always check the amount of sand and silex before filling the filter.