Who builds thier waterfalls out of natural stone not using a biofalls or waterfall box. I saw one the other day that looked like they just built it without a box and it looked like a perfect spring outlet. I couldn't determine how they built it without tearing it apart. I want to learn how to do this but I'm not sure how to without having a leaky waterfall. I assume you line it with liner and install the piping with a pipe boot. Any pointers would be great.