[Joe Bob]

The new to me Mercedes Diesel has a separate filler cap for this additive. https://www.walmart.com/ip/BLUEDEF-Diesel-Exhaust-Fluid-2-5-gal/16933407?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227010184782&wl0=&wl1=g&wl2=c&wl3=67020913849&wl4=pla-150230954449&wl5=9028890&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=16933407&wl13=&veh=sem#about-item

Does this additive go into a separate tank or does it mix in with the Diesel fuel and just has a separate filler hole? How much do you use if it is like a pre mix?

Thanks in advance.