Noticed the water level was low after peaking under our permeable cover. We marked the water level two weeks ago and we are down about 6 inches since then. The water in the pool is only about a foot deep! Should I add some water so that the walls don't collapse? I was planning on trying to open this wknd as the water temp is about 50. Obviously, we have a leak. What do we do next to figure out where the leak is? How do we know if it is a problem under the pool with the floor drain pipes? Is this something we can figure out ourselves, or should I call the pool company and prepare for a massive bill?