New pool owner here. (Pool itself is about 20 years old.. just got it replastered a couple months ago). Anyways, my skimmer has 2 holes. I assume one of the holes is attached to the main drain at bottom of pool (there’s 2 down there). Doesn’t this mean then that the skimmer pulls main drain water vertically through the main drain hole into the skimmer which then sucks that water into the pump? If so shouldn’t I feel water coming up out of the main drain hole? I don’t feel anything when I put my hand over it so I’m concerned the main drain plumbing might be blocked or is this normal? My pool equipment has total of 2 jandy valves on suction side.. one for the spa drain and the other one is for pool vacuum cleaner/main drain/skimmer combination. Thank you!