A basket system for a shale shaker, wherein the basket comprises: a front, solids discharge end and a rear, feed end, spaced apart by opposed first and second sides, wherein the feed end includes a fluid retaining wall; a lower screen deck frame mounted or mountable to the basket for supporting a lower screening surface and forming a lower screen deck in use, whereby the screening surface of the lower screen deck has a lower, feed receiving, end that is proximal to the fluid retaining wall at the rear end of the basket and a distal, higher, solids discharge end at the front end of the basket; wherein the fluid retaining wall includes a feed director extending rearwards and formed for directing an applied solids and liquid feed towards the front of the basket and onto the lower screen deck; and wherein the basket further includes a mounting for mounting at least one upper screen deck frame above the lower screen deck frame; and a mounting for a cover plate releasably attachable to the fluid retaining wall to cover the location for the feed director on the fluid retaining wall; and wherein the system further includes at least one upper screen deck frame and at least one cover plate; the cover plate comprises a mounting for mounting at least one upper screen deck frame above the lower screen deck frame; wherein the cover plate comprises two or more flanges projecting towards the front, solids discharge end and being downwards directed, providing a downwards directed surface for connecting to a front edge of two or more upper screen deck frames, one above the other, to form a stack of screen deck frames above the lower screen deck frame. a front, solids discharge end and a rear, feed end, spaced apart by opposed first and second sides, wherein the feed end includes a fluid retaining wall; a lower screen deck frame mounted or mountable to the basket for supporting a lower screening surface and forming a lower screen deck in use, whereby the screening surface of the lower screen deck has a lower, feed receiving, end that is proximal to the fluid retaining wall at the rear end of the basket and a distal, higher, solids discharge end at the front end of the basket; wherein the fluid retaining wall includes a feed director extending rearwards and formed for directing an applied solids and liquid feed towards the front of the basket and onto the lower screen deck; and wherein the basket further includes a mounting for mounting at least one upper screen deck frame above the lower screen deck frame; and a mounting for a cover plate releasably attachable to the fluid retaining wall to cover the location for the feed director on the fluid retaining wall; and wherein the system further includes at least one upper screen deck frame and at least one cover plate; the cover plate comprises a mounting for mounting at least one upper screen deck frame above the lower screen deck frame; wherein the cover plate comprises two or more flanges projecting towards the front, solids discharge end and being downwards directed, providing a downwards directed surface for connecting to a front edge of two or more upper screen deck frames, one above the other, to form a stack of screen deck frames above the lower screen deck frame.