I'm trying to figure out how or what this second hole is in the skimmer, I'm trying to use a pole and hose connected with attachment but have no luck with either side of the pools skimmer and its really rough right now trying to clean the pool. . . . ill upload more pictures if I'm able too I'm new to this forum and hoping for some help for my rookie self! I watched my dad run his in-ground pool all the time but we never had this box.