We've had the strangest problem with our waterfall. Pool is about 5 years old. Last year, it stopped working and I couldn't figure it out, so while the pump was on, I just jumped in the deep end of pool where there are two round grey things (returns of some sort?) on the pool wall. As soon as I jumped in, the waterfall came on. It worked great for several months and then the same thing happened. This time I just tapped on the round things and the waterfall started flowing. This has happened 3 or 4 times now, but this last time I just can't get water to come out. The waterfall is on a separate pump. I had someone come out and he just said to replace the pump. I called another guy and he said if the pump is still coming on, it's unlikely the pump is bad and that it will be $95 for him to diagnose. I'm at my wit's end on this thing. Any other suggestions? Thanks.