Was looking at the pond on Monday(27th) morning and found that the water was very low at about 8". I noticed some water over by a back bush, so it seems that the water is running off the water fall on an edge it is not suppose to. I refilled the pond to about 11" and let it run until about noon. I checked it again at noon and saw that it was getting low again, so I disconnected the pump and let it dry out a bit and make sure the leak isn't someplace else.
Tuesday night I started the pump back up and watched for the run off, but didn't see much that would cause it. The water level was at 10.5" and I filled it back up to about 12" and let it over night. Letting it set like that it seems the algae got a little agressive, so I put in about 40ml of algaecide.
This morning I did a little more checking and there was some run off toward the top of the spill way and it seems to be that the water tension is pulling the water over too far. I moved some rocks away from that area to see if that helps and going to let it run for a bit longer. It was down to 10.25" this morning and I am going to attempt to get it back up to 12" before work here.
Just checked it again, and it is down to 11.5" and have found the issue for sure. I went ahead and turned off the pump until I can find time to adjust the liner to be a bit higher. Which might be tomorrow night at the latest. Below is a picture of the leak.