I close my own pool every year and every year I end up running into the same problem. I've been meaning to make this post but never have. I'll skip to the issue, but after I put my filter in recirculate, I install my attachment for the air hose to the furthest return from the pad. I turn my compressor on and the next return will start bubbling, so I plug it. This makes the next return bubble, so I plug it. But the return or skimmers on the other side of the pool will not start bubbling. Now the first couple of years, I kept at it and they FINALLY started bubbling a little bit and I eventually got it closed. But last year, I got tired of messing with it and hired a guy to do it. He "said" he had no problems. So this year I move the attachment to every return in the pool but I get the same results. If I move the attachment to the far side (single return side), the other side won't bubble at all.
What am I doing wrong? All valves are open. Filter is in recirculate. It's the same problem every year. Am I just being impatient and need to allow the compressor to run for a long time?