I didnt know what else to call the plastic cone that the filter sits on, so I'm calling it a stack. Obviously a newbie here.

I went to change the spa's mineral insert that sits in the stack and noticed that sitting inside the stack was what appeared to be an old mineral insert. The instruction manual that came with the spa was pretty sparse on the info so I dont know what to do about getting that out. Its loose inside and it prevents a new mineral insert from correctly seating.

I hope this makes sense to someone. I'll include a pic:
Spa filter stack.jpg