Like the automobile, the very first bead biofilter was a breakthrough in technology. It offered pioneer pond keepers an alternative to archaic methods of filtering water. But like the Model T the very first model bead filter had its share of problems. As time goes by these problems are addressed by manufacturers and improvements are made. The hour-glass design of the bubble bead was found to bottle-neck the water flow and was ditched by many distributors in favor of a single round tank that resembles a pool filter.