Thanks for all the imput and patience with my question, but I guess I'm not presenting this clearly.
If I have two tanks, one with bio or #2 and one with svo and appropriate pre-heater lines, why can't I run bio/#2/svo through the heated line,as long as I do the start-up/ shutdown on Bio or #2 from the first tank? Is there a problem running bio or #2 through the heated svo line?
The situation I imagine is finding a cheap(haha) price for#2 while on the road and wanting to fill up the second tank that may have some residual svo in it.