[Gegrad]

I do the FW tank method too... but you have to sanitize the FW system in the spring regardless if you put it in the tank or not, so there is no time savings in the spring. There is, however, significant time savings in the fall by dumping it in the FW tank. And yes, my trailer is flat level and I use about 6 gallons of antifreeze in there and run the pump through until it is as pink as the bottle.