AA,
I recommend...........NONE. Over time microbes which live in diesel fuel mate, breed and party in you fuel over time. Add condensation in your tank and they are happy buggers.
If you use an additive, some types can actually kill these bugs. The problem is that they die & settle to the bottom of your fuel tank. This is the grey sludge you may see on your pick up tube screen. This can clog the flow at the worst possible time(especially during high throttle) at your filters & screen clogging can cause your engine to quit.
There are several schools of thought on this. You can find pros & cons for additives. My suggestion after research would be to clean you tank first if your having problems, especially if your fuel sits at half tank or lower for extended times. Hopefully have a primary 10 micron filter & secondary 2 micron filter.
I had these problems with clogging and after doing a thorough cleaning, I looked for a gas station that had good filtered fuel. My exxon station has fuel the color of water almost aviation fuel grade. Also i use my boat but keep the fuel around 3/4's full.
Another method people swear by is buying an in-line magnet piece found on the internet. The claims are it doesn't kill the microbes, but makes them sterile and they don't reproduce. Because your system constantly recirculates your fuel from tank to engine back to tank, back to engine, the bugs over time will be burned in your cylinders, not die & settle to the bottom as sludge.
I'm sure some folks will disagree with me but since doing the above on my boat, I no longer have any problems.
Hope this helps,
CR