Thanks ill try this and see what happens.Turn off the pump for 24 hours. Put a 5 gal. bucket in the pond filled with water to the same level as the pond water. Mark the waterline inside and outside the bucket. After 24 hours, compare levels.
If water in bucket is same level as water in pond, it’s either evaporation, or leak is in the plumbing or waterfall.
If water in pond is lower than water in bucket, then you have a leak in the pond.