I have an above ground pool that is 16 x 20 with a bottom drain. It started leaking two summers ago about an inch each day. I have never found any wet spots in the yard around the pool. Ive tried finding the location of the leak without any success. When I opened the pool this spring it was completed drained which leads me to believe its in the drain somewhere. I refilled the pool and left the bottom drain closed. This still didnt solve the problem. In fact, once I opened the bottom drain it seemed to lose less water than when it was closed. It iss still losing water daily. I know the water loss isnt from evaporation. Any suggestions?