I have the CircuPool Universal25 system and it's getting pretty old. The xxxx to control the chlorine production does not stay on the number it is set at and it's nearly impossible to select a number as it is too sensitive to movement. I'm considering upgrading to the RJ-20 system and wanted to know if the salt cell will fit into the plumbing connections I have in place for the Universal cell?? (CircuPool RJ-20 PLUS Salt Chlorine Generator)