I use the fuel dock in my home port,
I'm lazy, it easier, they have the big cattle boats pulling up all the time getting hundreds of gallons so their stock moves fast enough I'm not as concerned about water contamination, I'm not convinced that diesel from the gas station is pristine clean, it's prohibited in the marina to refuel at your dock and I don't use 25 gallons a year I bet. Mechanically it's okay, I think technically it's illegal cause taxes are different so they die road, farm and marine diesels different colors. Most enforcement I believe is directed towards commercial road vehicles using cheaper agricultural diesel, not really a concern for private citizen maybe.