Have a 16x24 Doughboy installed April/May 2012. Had it installed by contractor through pool store. 52" sidewall with about 24" above the ground the rest buried with a deck around part of it. No problems until just noticed the deck is about 6inhes off the top of the pool. Meaning the pool has sunk. The snow and ice started to melt and this is when we noticed. Why is this happening? Is this a problem with install? What can we do to correct? Pool appears to be sinking a little more on one side than the other, but the entire pool is sinking.