I finally found the air leak in my skimmer line that I asked about last month. I got the local leak detector experts to come out with their fancy equipment. The leak is in an underground pipe made of thin wall polybuteline. They said that these are trickier to fix than PVC. He said the glue often doesn't work well, and it might be best to cut out the leaking part, use clamps and connect the two ends with PVC. Does this sound correct to you, or is there something else I should know?