I have a 27' above ground, installed April 2012. The first season, no problems. This season huge creases have developed across the diameter of the pool. I lose 6" of water every 10 days and the liner is loose on the bottom. I do not see any visible signs of water leakage anywhere around the perimeter of the pool or the filter area. I am constantly putting water in to be able to run the filter and did not have to do this once last year. Of course, there was only a one year warrantee on installation which equates to a couple of months. Any ideas on how to find what the problem is and fix it? I also have a gorilla guard under the lining.