The water flows through the filter from bottom to top by means of a bypass of the main pump or an additional feed pump - optimally in the fluidized bed process. Alternatively, the simple upstream process (less water inflow) can also be used; in this case, however, regular rinsing is required. For this purpose, the inlet is increased considerably for a short time or additionally flushed with air - the drain connection can be used for the air supply.
The filter material POC+Globuli degrades completely within a few months and only needs to be refilled when the performance decreases. Choosing the right size is not easy, because the amount of POC+Globuli required depends very much on the nitrate formation rate of the aquarium. The filters may be oversized - if the nitrate and phosphate concentrations drop too low, part of the filter material can be removed and stored for future use.