I tried a couple different approaches last night and none of them
worked... ugh.

I'm going to swing by a pool store tonight to see if they have the
piece I need or any suggestions as to how to re-plug the filter.
Worst case scenario is that I just plug the hole with something and run
the filter this year, then buy a new filter next year. I think that
might be the way to go anyway.

Thanks for the help Richard.