So I recently purchased a used toy hauler. It has roughly 20 gal of gas in the hauler. The guy couldnt remember what octane it is, or how old it is. I dont have anywhere i can dump it. I was thinking of just adding some marine sta-bil (http://www.goldeagle.com/product/sta-bil-360-marine) to the tank, and run it until it is almost empty. My thought process is to use the marine since it is designed for water environments. That way if there is any water seperation in the tank it could help with any issues. I would then fill it up with 91 octane from that point on. The trailer has a pumping station that also uses the same gas, so I cant fill the rzr till I know it has good gas in the tank. Do you think that is a good plan? Im open to suggestions.

Thanks!