I closed my pool for the first time last year on my own. All seemed to go well. I reused the gizmo that the pool company used when they closed the previous year.
As we have an auto-cover, I have to keep the water level up to normal - about halfway up the skimmer. I thought it looked low, so since today was the first warm day we had, I opened the cover. Sure enough, the water level is to the bottom of the skimmer. So I'm obviously nervous. I took the stopped out of the top of the gizmo and peeked in, and while it is wet in there, there's no evidence of water in the pipe and the gizmo is on tight.
I guess I'll have to wait until closer to May when I really open things up. I have the hose in now to add some water. I'll check again in a week or so and see if it's holding. Not the best feeling right now.