Stanadyne Performance Formula 5 Gallon Pail Treats 2,500 gallons diesel fuel per Pail Note: All Stanadyne Diesel Fuel Additives can be blended with each other and "double-dosing" is not damaging - although it may not provide twice the benefit. Where engine and vehicle OEMs have approved Stanadyne, most of them recommend Performance Formula, which should be used year-round to ensure protection against fuel related problems.