I have a customer that is wanting to add a waterfall to their existing pond. They were displeased with their last filter and pump. So I did some research and I went to a place in town that specializes in ponds and waterfalls. I have a 7' dia. pond and he was telling me that they take filtermedia and put it in a milk crate. This is their filter. It surrounds the pump. In the smaller pond feeding the pond they also have the same thing. Has anyone done this? I am thinking I could make something that looks more professional. But I like the idea. Looking at the aquascape filters, its basically the same principal. Also I was thinking of using a 1500 gph pump for this 900 gallon pond. The waterfall will be up 4 ft. Will this pump be suffecient to make a gushing waterfall?