There is something between the vinyl liner and the pool wall in the deep end, just above the seam where the wall and the downslope meet. (about 6" from the corner). Can't tell if it is a nail laying on its side, sand that got in bewteen the liner or what. Not poking through ... yet. The liner was changed about 8 years ago .. by previous homeowners. Must have been there ever since. With the pressure of the water, nothing could make its way in. The question is, should I drain half the pool down to get at it ... to pull the liner back and remove whatever it is ... or just put a heavy patch over the area to protect against possible future puncture? The area is about 1/8" wide by 2" long going from the seam upward. Strange! Just want to address it now before it becomes an issue some day.