Every year I open my pool since 2016 my water is always full (Nassau, NY). This year my water is almost only half and below the skimmer so I am suspecting a leak. I tried to use it (Memorial day weekend) and put a tape on the water level on my skimmer (Friday) to measure how much water i will lose and it lost water again by a lot by Monday (check the 3rd pic). My liner was changed last year could that be the cause of the leak? or could it be somewhere else. 
