We claim the ornamental design for a dishwasher tub bottom, as shown and described.
FIG. 1 is a front perspective view of our new design for a dishwasher tub bottom shown in its environment;
FIG. 2 is a front, right perspective view of the dishwasher tub bottom of FIG. 1;
FIG. 3 is a front elevation view of the dishwasher tub bottom of FIG. 1;
FIG. 4 is a back elevation view of the dishwasher tub bottom of FIG. 1;
FIG. 5 is a right elevation view of the dishwasher tub bottom of FIG. 1;
FIG. 6 is a left elevation view of the dishwasher tub bottom of FIG. 1;
FIG. 7 is a top plan view of the dishwasher tub bottom of FIG. 1;
FIG. 8 is a bottom plan view of the dishwasher tub bottom of FIG. 1; and,
FIG. 9 is a cross-sectional view of the dishwasher tub bottom of FIG. 1.
The broken lines in FIGS. 1-9 form no part of the claimed design. FIGS. 2-9 show the dishwasher tub bottom enlarged relative to that shown in FIG. 1 with the dishwasher tub bottom in its environment.