yeeahhhh, sounds like you've got a leak somewhere! did you take pics of the bottom before it filled? have someone take a look at the pics, see if there is an area on the pics that could have caused problems. i can not imagine that much evaparation in that time period. did you dam a ravine, or dig a hole. the water will soak the area some, but i can't imagine 5 feet worth! there are a lot of previous topics on this website about options such as bentonite, liners and some other stuff. good luck
