Sorry if I am using any terminology wrong. If you look at the below picture I swiped from Google (this is not my pool), you will see the installer caulking between the top of the tile line and below (what I think is called) the coping. In my pool I am afraid that this line of caulking will soon need replacing. I am wondering what type of caulking I would need. Also, when would you consider it a problem where it needs replacement? Some (most) walls of my pool are fine, while some others have small (maybe 1/4") gaps around the line of caulking.