A filter assembly for filtering water in an aquatic structure having a housing with a flow inlet and a flow outlet and filter media between the flow inlet and the flow outlet. A vortex distributor is supported in the housing to distribute fluid evenly over the filter media and partially separate debris from the fluid. The vortex distributor has a conically shaped body portion with an upper side, a lower side and a vortex opening. The vortex opening is substantially centered in the body portion and a plurality of vanes are supported on the upper side of the body portion around the vortex opening, the vanes curving away from the vortex opening to form a substantially planar upper surface.