[hypoxia]

Others will chime in with more experience hopefully.  Newell should be able to tell you what type of plastic it is.  There are plastic epoxy's that may work.  If it is in an area that you can wrap "Rescue Tape" around it, that worked for me on a fresh water tank for a few years.  In the past, I repaired a black water tank with the putty epoxy sticks you knead, then apply.