We have a fiberglass pool with a tanning ledge that spills into the pool. The tanning ledge has two returns and two fountains. The main pool holds water with the pump running, as long as the tanning ledge returns and fountains are off - so no water spilling over into pool. If I run The tanning ledge with only the returns or only the fountains the pool still leaks. The ledge has a river rock tile with Novagard caulk between the rocks. I call It a tile because it came with a mesh backing like tile. We had a few holes in the caulk but sealed them with silicone, so I dont Know how water would penetrate the caulk? It’s Novagard 700-165. We had a leak detection company come out and tested everything. All lines were pressure tested and were fine. The tanning ledge holds water when off. Where the heck is the leak?!! I’m so frustrated. It’s about 1-1/2 to 2” a day. Entire pool is 16 thousand gallons so a lot of water is leaking. The leaking water seems go around the outside of the pool.m underground. We have an opening to that and can see that the water gets higher when leaking and lower when not leaking. Help!