First time opening a pool. Water is trickling out of my filter's waste port. Multi-port valve (MPV) is aligned correctly. Pump always turned off before changing settings. When analyzing the spider gasket, I noticed one small section (.25") kept popping out of place and would allow grass / debris to get stuck between the gasket and the plastic. Drying the MPV head and spider gasket and replacing didn't work. I then used RTV silicone to apply the gasket and waited 24 hours to replace but the trickling remained. Gasket integrity seems fine and even before applying the silicone, it had a snug fit.
After thinking about it as I'm writing this, a concurrent observation along with this issue is that I do see a small pinch of sand in one of the MPV compartments and there is maybe half a cup of sand at the bottom of the pool near the return. This is starting to sound worse than I thought! Any ideas?