An apparatus for separating solids from a drilling fluid that includes a basket having two opposed spaced-apart side walls having first ends and second ends, the first ends spaced apart by an end wall connected to each of the side walls, the basket further including a bottom wall through which a fluid outlet passage is defined, a plurality of screening surfaces having a front edge and a back edge and positioned within the basket between the side walls with each screening surface spaced apart vertically from adjacent screening surfaces and the back edge spaced apart from the end wall of the basket, wherein the back edge of each screening surface is lower than the front edge of the corresponding screening surface, a plurality of weirs, each weir retained along the back edge of a corresponding screening surface and spaced apart from the end wall to define a fluid passage between each weir and the end wall, wherein each weir has a top edge extending to a weir height above the back edge of the corresponding screening surface and the top edge is lower than the front edge of the corresponding screening surface, at least one flow director catching unseparated drilling fluid in the fluid passage and directing the unseparated drilling fluid onto a lower screen, and wherein fluid in the fluid passage between the lowermost screen and the end wall is directed to a spillover fluid outlet is disclosed.