So the question is what do you Suburban RV water heater owners use as an anode rod magnesium or aluminum and why?
My understanding is a magnesium rod protects better but is faster to be used up and more expensive and aluminum is better for hard water use, last longer and is cheaper.
Judging by the state of my recent anode rod from a 2 1/2-year-old tank it must have been magnesium.
When I went to buy a replacement rod the local RV parts shop only had aluminum when I asked the parts guys said that's all the sold and used. Funny because the water in these parts is super soft.
I did see magnesium at Canadian Tire but there were 49 bucks CAD! versus about 20 for aluminum.
I use magnesium. I have found that the aluminum rods last longer but the cost isn't much different. I replace the rod yearly even though it isn't completely used up. This is the stock anode rod after one year old. Since we don't winterize the tank always has water in it. A good flush once a year or more is a good idea even if the rod still has some life and you choose to keep using it.
Found this official looking video by Mark Polk done for Suburban company.
Looks like they come with OEM with magnesium but aluminum can be used for some water conditions.