Has anyone built one, worked on one, or have one? The reason I ask. I want to build one for my backyard, a small one, in the back corner of my planter. The block walls are 7' high and the planter is 5' deep. I figure that's plenty of space. I have tons of big 18" or so size rocks all over my back and front yards to use. I just need a pump and pond...I'm guessing. I'd like the waterfall to be 7' high, or close to that. Nothing fancy, or expensive. I figure I can buy the pump and pond anywhere just not sure if I need to match anything up as far as size and gph.