We are working on the designs for our pool that we are building and I had some questions about liners. We are building a 21' round pool with concrete walls and a concrete floor and plan to use a liner (the plan is to also line the walls and floor with foam to protect the liner and make a softer surface). The idea was that if we go with a common 21' pool we could just use a normal Latham GLI or Swimline liner. Is there any reason we wouldn't be able to do this?