I have a rotten egg smell when I run the hot water. I was told to replace the anode rod. Does it matter what kind? Aluminum, magnesium or zinc?

Hard water is a thing to manage. When you have sulfur bacteria it attacks the anode rod making a sulfur smell replacing the anode rod will not help this. I suggest you contact Crystal Clear Water Services they can tell you what type of filter you need to get rid of that sulfur smell

Magnesium I think that might be the one not sure you might have to call them and might want to get your water checked if you use hard water

Thank you for the answers. I have a water softener.