One of the advantages of the JBL CristalProfi external filter is the inner structure with the top mounted pre-filter which is easily accessible and thus easy and fast to clean.
Pre-filters are there to catch the coarse dirt which is sucked into the filter so that it doesn’t clog the underlying filter material. This filter basket has been designed to prevent the coarse waste from clogging the pre-filters, which can unfortunately happen quickly. It now contains one large one-piece pre-filter mat only with at least the double surface of its predecessor instead of 2 small externally arranged pre-filter mats.
This way the pre-filter doesn’t clog as quickly and the high filter performance of the external filter is maintained.