An ultrasonic probe (100, 200, 300, 400) for sensing a liquid level within a container (159, 259), the ultrasonic probe comprising: a barrel (123, 223, 323, 423) extending downwardly from a fitting assembly and comprising an internal volume (146, 246, 346, 446) defined by an inner tube (132, 232, 332, 432) and a conduit (144, 244, 344, 444) disposed longitudinally within the barrel, the inner tube having a longitudinal axis and a lower end that is distal to the fitting assembly, the barrel having a length; and a plurality of ultrasonic sensors (156, 256, 355, 356, 456, 177, 277, 377, 477) located within the internal volume (146, 246, 346, 446) of the barrel, each of the plurality of ultrasonic sensors configured to emit sound waves in response to received electronic signals, each of the plurality of ultrasonic sensors having a vertical spacing; wherein at least one of the plurality of ultrasonic sensors (156, 256, 355, 356, 456) is affixed to the inner tube (132, 232, 332, 432) at a location and in an orientation adapted to emit sound waves across the conduit (144, 244, 344, 444) of the barrel in response to a received electronic signal; and wherein the plurality of ultrasonic sensors includes an upper group (256a-256c, 456a-456f) comprising at least three ultrasonic sensors and a lower group (256i-256l, 456g-456l) comprising at least three ultrasonic sensors, the ultrasonic sensors of the upper group being located further from the lower end of the inner tube than any of the ultrasonic sensors of the lower group, the vertical spacing of each of the ultrasonic sensors in the lower group being less than the vertical spacing of any of the ultrasonic sensors in the upper group. a barrel (123, 223, 323, 423) extending downwardly from a fitting assembly and comprising an internal volume (146, 246, 346, 446) defined by an inner tube (132, 232, 332, 432) and a conduit (144, 244, 344, 444) disposed longitudinally within the barrel, the inner tube having a longitudinal axis and a lower end that is distal to the fitting assembly, the barrel having a length; and a plurality of ultrasonic sensors (156, 256, 355, 356, 456, 177, 277, 377, 477) located within the internal volume (146, 246, 346, 446) of the barrel, each of the plurality of ultrasonic sensors configured to emit sound waves in response to received electronic signals, each of the plurality of ultrasonic sensors having a vertical spacing; wherein at least one of the plurality of ultrasonic sensors (156, 256, 355, 356, 456) is affixed to the inner tube (132, 232, 332, 432) at a location and in an orientation adapted to emit sound waves across the conduit (144, 244, 344, 444) of the barrel in response to a received electronic signal; and wherein the plurality of ultrasonic sensors includes an upper group (256a-256c, 456a-456f) comprising at least three ultrasonic sensors and a lower group (256i-256l, 456g-456l) comprising at least three ultrasonic sensors, the ultrasonic sensors of the upper group being located further from the lower end of the inner tube than any of the ultrasonic sensors of the lower group, the vertical spacing of each of the ultrasonic sensors in the lower group being less than the vertical spacing of any of the ultrasonic sensors in the upper group.