A couple of weeks ago I helped a Fellow Football Coach close his pool. I know how to do mine so we followed the same procedure for his til we came to his Main Drain.
The problem is this, while mine has a dedicated line to my pump, his is plumbed in this manner.
One Main Drain, pipe leads to bottom of Skimmer, then there is a plug/nut there to shut it off when vacuuming., the other skimmer line runs back to his pump/filter. We blew out this line, added anti freeze and place a plug in it. Ok for step 1, but there is no way to blow out the main drain line, and when we place the plug/nut there, the water is directly below it.
I am worried this might freeze up in our area and have no way to freeze to.
Would you leave this open, fill the skimmer slowly with Antifreeze and hope that when the water down there freezes it will then work its way up to the antifreeze and have a way to grow rather then breaking some piping?