Why not just use foam rope?

[cbridges]

Like many people visiting the forum, I have an inground with the main drain line that runs to the bottom of the skimmer, thus joining the main suction line. The advice I've got from many threads and many pool people where I live is to blow the main drain line until bubbles start to appear, and then cap the line at the bottom of the skimmer, either using a device or a rubber stopper, so that air stays in the line. A few other sources, however, seem to recommend using foam rope--taking four feet of foam rope, folding in half, putting in the main drain line at the bottom of the skimmer, and then capping the line. Would this not be a far better and easier arrangement? Foam rope first displaces the water in the top two feet of pipe (far beneath the frost level) and, if any water remaining in the line around the foam rope does freeze, well, the rope absorbs any expansion. Can anyone comment--hopefully as soon as possible, as I'm winterizing here in British Columbia today. Thanks!

[hzz]

I have the same setup as you. I never blow the main drain line out. I just put the foam rope into it and then cap it off.

I lower the pool level to just below the return jets. Never had a problem yet here in Toronto.

[cbridges]

Thanks for the confirmation. Just can't understand why more people don't do this!

[Poconos]

I guess being able to use the rope would depend on the plumbing configuration. Access, bends, etc. If I had a main drain you could bet I would have access to the pipe where it goes straight to the drain.
Al