I am taking care of my cousins pool and the skimmer cover has these letters WC 27-92 and after reading about another post on the forums I saw that these two holes may or may not be connected somewhere. This is a built in pool. So I took a towel and attempted to plug up the hole with the main suction and I could hear the pump straining big time. Except the basket for the leaves it catches there is nothing else that in in there. I have read about the space ship or the twinkie that may or may not direct the suction to the bottom drain. So, my question is, what would the adapters do to direct suction to the bottom? When the main suction hole was plugged with the rag, why didn't it begin taking in water from the other hole or the bottom drain? She also has this adapter that sucks leaves from the bottom of the pool which we'll get to some other time. Thanks in advance.