Was that some kind of pre-fab waterfall at the top? And were any of the rocks or falls mortared? Or is loose stacked with enough water to provide the falls? Did you use a filter? Our first experimental pond at the home has no filter, and stays crystal clear all year. It does have a filter "system" in a way. The intake for the pump is under a small heap of pea gravel. The water is drawn in through the pea gravel, and then up. Same basic system as some fish aquariums.