The thousands of beads in any brand of bead filter, no matter how well it’s constructed, will eventually cake up, especially in ponds that are overloaded with fish and plants. As odd as it seems, plants in a pond add more dirt and debris to the water than fish alone. An overabundance of string algae can literally glue the beads together after a season of use. If your bead filter is needing to be backwashed more than once a week it’s time for maintenance.