What is an effective way to find where the water is leaking? I've rented a 2500 gph pump and went from the pond to the first level and the water level stayed the same, did this on each level and nothing changed, so I thought it must be at the outflow from the falls. I re-did all the foam etc and it's still losing water. Is there something you have found over the course of time to trace the leak? It;s driving me absolutely bonkers!!!!!!! Here's what it looks like now. I've checked all the edges....ARGH!!!!