The ornamental design for a base for a spafoot bath, as shown and described.
FIG. 1 is a front perspective view of a base for a spa foot bath showing my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a left side view thereof; the right side view being a mirror image thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a perspective view of the base shown with a disclaimed chair and disclaimed additional portions of a spa foot bath.
The broken line showing of a chair and the remainder of the spa foot bath in FIG. 7 and the domed region of the spa foot bath throughout the figures is for illustrative purposes only and forms no part of the claimed design. The unshown bottom of the base forms no part of the claimed design.