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Depending on the initial water source, sometimes leaving the hot water tank full when stored between camping trips can produce a smell, I've had it happen to me so I drain my tank between trips.
Sounds like it would be best to sanitize your entire system with a bleach solution..., refer to your owners manual for directions. I do this once in the fall and again in the spring.
Also, the particular hot water tank you have is aluminum so an anode rod isn't required. Please note that it's important to always use a plastic drain plug because a metal plug will initiate corrosion (dis-similar metals). When removing the plastic plug clean any residue that is built up inside the plug.