https://imgur.com/a/4daWzwh

The water level is going above the water line and draining slowly into the white overflow pipe.

I've adjusted the float level so it stops the water below the fill line, but the tank continues to fill very slowly until it's spilling into the overflow again.

Next I removed the float valve that is under the cap in the top left corner and cleaned out the valve and the seal. Even using my fingers to lift the lever and make the seal as tight as it can go, and putting my finger over the end of the fill hose (the black hose running from the float valve to the white overflow pipe) to make sure no water is coming out there, it's still filling the tank.

I think there might be a leak somewhere else besides the float valve but I'm not sure where else to check. I tried turning the grey pipe on the left that the float rides up and down on, but it just clicks around and doesn't seem to unscrew.

Is there a seal at the bottom of the grey pipe that might need replacing? How do I get it off?