After enjoying our backyard waterfall for over a year, some serious tweaking came due. Despite our treating the water, the heat of summer caused a lot of algae to grow in the bottom of the pond, and quite a bit of debris had fallen in, like leaves and dust, slowing down the flow noticeably. And worst of all, when I constructed it, no rocks were placed around the sides of the pond, and the black liner showed. Not many Sierra streams reveal plastic lining. For the first step...