I had the Hayward S166T sand filter installed at the start of the summer 3 years ago for an above ground pool.
It recently started putting dirt back into the pool as soon as I started to vacuum. I pulled the filter apart to replace the sand and found the laterals sitting on top of the sand and the center pipe so far up the valve body connection that when I pulled it apart I found the top 3 inches split/crushed. (I have pictures if anyone wants to see them.)
The question I have is was this mis-assembled by the installer? Or can the laterals "walk" up the
sand by some manner?