Man what a drag. Better get yourself a screw gun and utility knife. If you have to cut the liner there is a special tape made for that stuff when you put it back together. I don’t know of any way of finding it other than just diving it. It’s not nice cutting into the bottom of it but it’s not the end of the world either. The floor will only get worse until you find the source and replacing the floor can be a major major deal. I’ve had a leak in my supply line and have been running off the pump until I can get around to it.
Good luck!!!!