Originally Posted by OldCoot
Toilet valve should not get any sediment from the water heater or the anode due to the fact that the toilet uses cold water.
However, the cold water lines feed in to the HW tank at the bottom. If (and that's a big if) the lines were somehow pulling from the tank that could explain the sediment from the tank flowing to the toilet along the cold lines. Normally this shouldn't be a concern as the water pump should
be applying enough pressure on the lines to prevent that from happening. It would take a lot of pressure to force the sediment up to the hot water line, but a lack of pressure would easily allow sediment back into the cold lines.
If this were me I'd be looking at the plumbing between the pump and the tank and seeing if anything there could explain how the sediment is flowing back on the cold water side.