So my Hayward was acting funny. It was draining as well as filtering. I lost water by the next day. I ordered a new gasket online. However, I did some investigation to see what was wrong with the old gasket. I think many people (like myself) assume the gasket must be bad and must be replaced. Quite often the gasket adhesive separates from the base and it needs to be re-glued down. I removed the old gasket and inspected it for tears and cuts (a little worn but not bad). I removed the old adhesive and dried out the groove. I applied RTV (automotive RTV) to the groove and temporary assembled the head so it can press down on the gasket (squeezing the excess out). I waited 24 hours, opened it up and removed the excess and reassembled it. No leaks at all. It's been running for a few days now.