If I remember correctly, the difference between 25xx and 28xx tanks is that in 28xx tank, there are edges to hold prints. But the edges are not good for film.
I have a 2521 and a 2551 (like the 2553). As expected, the 2551 does not have the print edges. But the 2521 has the edges to hold prints. It is built in exact same way as the 2820 test drum. So I do not know if 2521 is the same as the 2820, or my 2521 has the wrong Jobo label.
I have been using the 2521 to test print paper strips and to develop film with 2502 reels. The films come out quite nicely.