A diffuser assembly for diffusing a fluid from a fluid source into a medium to aerate the medium. The diffuser assembly including a diffuser body in fluid communication with the fluid source and a membrane connected to the diffuser body. The membrane is circular and includes a slitting pattern divided into a series of similar angular segments. The segments are positioned adjacent each other in a circular arrangement to substantially cover the membrane. Each segment includes a plurality of rows each having a plurality of slits. The slits within the segment are arranged in a parallelogram pattern. A first line extending between adjacent slits in a common row is substantially the same length as a second line extending between adjacent slits in adjacent rows.