Do you mean Diesel Fuel Additive? The abbreviations go wild on these forums.
I've had 2 diesel cars. First one had 195,000 when I sold it. One now has only 183,000. I've only had to use Chevron's Red Line twice in the newest one. Only use it when the engine pings, only been twice, the 2nd time after being stored for 4 1/2 years with diesel kinda brown in the tank.
The ping occurs at steady, lightly loaded, speed, not like a gasoline engine's ping.
Chevron Red Line will stop it with one application.
No need for any other additive that I know of.
Ralph