My 2003 Tracker has a 21 gal. gas tank. In 2018 I removed all the old fuel & refilled with 100% gas. I also treated the fuel at that time. For various reasons I did not get to use the boat much the past 2 years. The tank is about 1/2 full. Question: Should I add fuel treatment before winter layup. I live in Southern Illinois so we don't get a lot of real cold weather. Also the boat is garage kept. Appreciate everyone's input.