MultiCyclone pre-filters up to 80% of the filter’s incoming dirt load easing the workload of the swimming pool filter. As the MultiCyclone intercepts more and more dirt, the flow rate remains unchanged. The installation of a MultiCyclone as a pre-filter to a sand filter can reduce its backwash frequency to once per year, resulting in a saving of up to 7, 000 litres of water per year for an average domestic sized swimming pool. The installation of a MultiCyclone as a pre-filter to a cartridge filter can reduce filter cartridge cleaning and replacement to once per swimming season and even up to once per year, depending on the size of the cartridge filter. The MultiCyclone works on the basis of centrifugal water filtration. There are no moving parts to wear and tear, and no filter media to clean or replace.