I thought the darn thing was gone. I haven't heard it tapping for 2 months now. I was gone for the weekend and my clam was gone. I am going to take each rock out and soak it in fresh water. I was wondering how ling to saok the rock? I was thinkng about 15 to 20 minutes!?!? Will this this be long enough or go for longer or shorter time? Thanks in advance!!!!!!