So awoke this am to the pool returns spitting out air inter-mixed with water, "What the heck?". Go to the pump and the basket is half full of air. Turn the valve from mostly skimmer to main drain and that cured a bit of it but still sucking air. Go around to the skimmers and in one of them, the floating temp gauge had gotten stuck behind the weir and was holding the door closed. Removed that dumb thing from the pool entirely until I figure out a way to anchor it somehow. Lesson learned and thankfully the pump wasn't running dry.
My temp gauge is tied to my skimmer lid.