I tried to follow the instruction in this forum to close the pool, everything has been working well so far. Just one question about the main drain blow out.
I attached air compressor hose on the drain of the pump, and switched the multi-valve port to receip. (I already backwash and open the drain plug of the filter, so I think I can bypass the filter. Please correct me if I am wrong.) After blowed out and blocked skimmers, return lines, main drain is the last one that bubbles coming out. Then I turn off the valve switch of the main drain, followed by unplug the air compressor. Now the question is how should I check if there is any (air) leaking from main drain valve that I just turned off. The valve level is above the pool water level and the main drain is at 9' deep in the pool. The main drain valve actually works well for water, the evidence I have is when I vaccum the debris of the pool, I turned it off, leaving only skimmers on. I can definitely tell that the main drain valve works for water. But I cannot tell if it works for air. I wonder in my case, if there is any leaking of air, during the winter, is the pipe gonna freeze and cracked? (Last year, the pool company did winterizing for me and this was all what they did and it works. I am just a little bit worry, since it is the 1st time I did this myself.)
Btw, I live in Long island NY state.