I am thinking about adding a 2nd fuel tank I might end up using it for SVO/WVO but for now it is for extending my range. I am thinking about a manual 3 way valve that I can switch myself whilst driving and to keep it simple wondered if looping the fuel return causes any problems? The only one I could really think of was getting air out of system but my fuel filter has a bleed nipple on top for that. So what are the pro's & cons. What have I missed?