There was a discussion on my YouTube channel whether any of the tanks might be suitable for processing APS films. The Rondix is the only candidate and so I took a processed film to see what would happen. The cassette fitted so I stapled the end the APS film to a short length of 35 mm film in order to enable the film to be gripped by the central spindle. So far so good, but the film chamber was too wide and the film soon became tangled. Failure.

However, if, after perfecting a 3D-printed standard Rondix for 35 mm, somebody could attempt a narrow Rondix especially for APS film then some APS users (who have plenty of old film available but a diminishing number of commercial processors) might be very happy.