I'm doing a pond re-do and am leaving the skimmer in place, re-attaching the new liner....my question- the skimmer appears to be an Easy Pro Skimmer. It has two chambers with brushes. The left chamber houses the pump and the right chamber is where the skimmer opening is. In the left chamber, the flexible pvc enters the skimmer, but in the right chamber, there is another outlet. I haven't dug around the skimmer yet to see what that opening is for....does anyone know?