Filter & Waterfall pumps are designed to be able to move reasonable sized solids in the water in which they pump. This means they are able to have strainers with wide holes meaning more particles and sediment can be moved to a filter for removal from a pond. This means the pump does not clog up so easily or frequently as it would with a finer strainer reducing maintenance. These pumps are not suitable for hose/pipe outlets with very fine apertures like spray heads for fountains.