I had a 30 ft above-ground round pool (Grove Park, Sunenterprises) installed ten days ago and just finished with pump/filter install four days ago. Since filling the pool to the "run" water level, the water level has dropped about 3 inches. No visible leaks in the pump/filter system. Could the liner be stretching or some settling with the pool? Outside temps are in the upper 60's so I don't think evaporation would be causing the drop. Any ideas greatly appreciated.