Vinyl liner pool. This is our first year with this pool. I think there is a leak. There are two marks on skimmer, high and low water level marks. I had it on the high side mark and in 3 days the water went down one inch. I added water for about 6 hours and filled to high water mark on skimmer. In 3 days it when down 1 inch. This time I'm not going to add any water to see if it drops. What else can I do to find any leaks. If it levels out then I know therr is a rip in vinyl. The pipes were pressure tested in March when we bought the house and pool guy say, all good.