yep when water level stops falling your leak is somewhere at that level .Do you have just one liner or several .I had a plants roots grow beteen the 2 liners and I could not find the leak turned out the plants roots were wicking the water up .I pulled 5 handfuls of roots out and replaced the liner and rebuilt the water fall .I also know replacing the liner is a hassle after neighbors dog ripped mine and good gosh that old liner was sucked to the soil , I was amazed at how hard it was to get out .Welcome to the world of ponding :cheerful: leaks turn out to be a big head ache .Oh you never said how much water you were loosing and some will happen with all those water features you have and all the splashing they cause ,Water evaporates fast in heat .I think I read on here how much you can loose each day .I thought a year after I put my bigger one in that I had a leak and it turned out to be the deer stopping by to drink during a drought here .I got them a water trough and refill it each day ,right now all we have been getting is rain .