As part of ongoing product improvements, filter balls may have slightly different diameters or appear more voluminous. This is completely normal and due to the production process. However, this does not affect the filter performance—regardless of the size or volume of the filter balls. Your water quality continues to be optimally protected.

In principle, it is possible to add Filter Balls to any conventional sand or cartridge filter system without any problems. 
For cartridge filter systems, please use the filter net included in the scope of delivery. Please refer to the technical data specified in the online shop for the correct filling quantity of filter medium for your model.
Please also note that you must not backwash with filter balls, as this can cause filter balls to get into the system and cause damage. When filling a two-chamber system, it is important that no filter balls get into the fresh water area. This could otherwise lead to blockages in the filter system and in the pipework.
If filter balls are used as a filter medium, do not use flock cartridges for water treatment.

Backwashing would pull the Filter Balls or filter Wool Flakes into the lines and clog them. The resulting pressure in the filter tank would be too high and could damage the filter tank.

Depending on the degree of soiling, the filter medium should be cleaned with a garden hose approximately every fortnight and then dried in the sun.