I have the Classic RJ30. I am looking to replace the large rubber rings that the cell housing fits onto the pvc piping and the o-rings that are on the cell housing as well?
These are the three O-Rings needed that create the water seal on your system. Take a look at pages 19-22 here for exactly what you need to do to replace them: https://www.circupool.com/assets/doc/CircuPool-RJ-Classic-Manual.pdf