Pool pad? Swimming Pool question?

Question:is a pool pad for keeping the sharp stuff in the sand from coming through the liner of the pool?

Answers:
need more info...
is this something your installer is putting between the layer of sand and the liner? If so it could be just a membrain that does just that. keeps both the liner safe from any impurities in the sand and add a little rigidity to the liner bottom so you dont tear it as easily.

Hope this helps