You should use a filter between the buddy and the hose or they also sell a hose that does not require a filter. There were apparently some issues with certain hoses contaminating the heater and it would stop working, thus the need for the filter.
I also read where it was oil from the larger tanks that was doing it, not sure what causes the problem but Mr. Heater suggests using a filter or the proper hose. It will say right on the package when you buy the hose if it doesn’t require the filter.