I'm getting ready to winterize my N2U 2013 Palomino Y-series 4127 for the first time and I have a question about the fresh water tank. It sits below the floor of the camper, just behind the axle. I've emptied it as best I can (tilted the camper back and to the side with the BAL leveler), but it bulges down in the middle and won't drain all the way. I put a bottle jack below and pushed up a bit to get more water out, but there's at least a half-gallon of water still in there. Do I need to worry about draining the tank dry, or will it be okay for a little water to be in there over the winter? Should I pour in some RV antifreeze to mix with the remaining water?