I just received my new Ace 250 today. I live on the west coast of Florida so I assembled the unit, watched the CD and headed for the beach. Very disappointed. I tried an experiment by digging a 4 inch deep hole in the sand. I first placed a quarter, then a dime and finally a penny in the whole and filled with sand. The 250 didn't make a sound. I then opened the whole for each coin and still nothing. It didn't detect the coins until they were at approximately 2 inches deep. Settings were factory defaults. Can anyone comment on this?