First year closing the pool, 10000 gal. it has 2 bottom drains. The drains lead to a pipe coming out of the ground near the equipment. there is currently a hayward 3 way valve connected to it leading to skimmer and pump. the previous homeowners left a cap for the bottom drain pipe with a strange looking metal fitting on top. Is there some sort of attachment for an air compressor to fit to this and its some kind of one way valve? Im pretty lost here.
Thanks for any help.