These are some of the things I've learned over the years taking care of my sponge filters and thought it may come in handy for some people.   If you have any additional tricks, feel free to share!  We all need to help each other.   Most of my experience has been with the XY 2831, however most of the models are pretty similar.  The pieces are like legos.  Pop them off, put them together.   Double to Single   So you can make a double a single if needed, by rearranging the pieces.  Pop off