Winter-Proofing your RV in cold locations....

By tank heater my assumption is that he means electric heaters that you can turn on to keep your tanks from freezing. To know what sort of options you might have when it comes to cold weather we really need to know more about your specific RV. It's been years since I owned a motorhome, and the one I had didn't have any heat options for the tanks. My last two towables used the furnace heat to keep the underbelly warm, and as long as I used the furnace they were good down to around zero. A TT I owned prior to that had the tanks, and many of the plumbing lines completely exposed underneath and didn't handle cold weather well at all. There is a lot of variation so good advice will only come with knowing what you're using.