I don't see the picture either. But it is normal for sediment to flush out of the tank style water heaters.
That said, there are differences. I think one brand is made with an aluminium tank and the other with steel. Corrosion protection and sediment reduction works differently in each. If your RV's water heater is an Atwood than it does not require an Anode Rod (pictured above) If it is a Suburban Water heater than in all likelihood it does require an Anode Rod.