Humidification tub bottom

FIG. 1 is a front perspective view of a humidification tub bottom showing an embodiment of our new design;

FIG. 2 is another perspective view thereof shown in isolation;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a left side view thereof; and,

FIG. 9 is a bottom perspective view thereof.

The broken lines represent environmental structure or unclaimed portions of the humidification tub bottom and do not form a portion of the claimed design.