A container is mounted with respect to a fluid processing device using first and second supports, with the first support engaging a first portion of the container and the second support engaging a second portion of the container. The second support is positioned above or below the first support. The first and second supports cooperate to restrain the container in a fixed orientation, such as aligning an image on the container with an optical detector of a fluid processing device. The first and second supports may be components of a fixture that is separate from a surface of the fluid processing device or may themselves be incorporated into and extend from the surface of the fluid processing device.
