Add to nearly empty tank- how much does it matter?

[rationull]

I'm going on a road trip tomorrow, and have a bottle of Regane I was going to throw in for the heck of it. The bottle says to dump it in on a nearly empty tank. When it's convenient to get gas in the morning, I'm going to have probably 4 gallons left in the tank (out of 13). Should I go ahead and dump it in or should I wait until the return trip and see if I have a "better" opportunity?

If they just want the stuff to mix in well, it seems like anything below about a half tank would be good enough...

 

[beast3300]

Dump in it, your good.

 

[sicko]

Dump it in, you're going to fill up directly on top of it. As I understand it (though I could be wrong) the reason they say nearly empty tank is b/c they want you to fill up directly after adding it to the tank to mix it with the fuel. I could easily be mistaken but that's what I was told.

Drive to the gas station, turn off car, add bottle of fuel system cleaner, add gas, start car and enjoy road trip

 

[DieselTech]

entire bottle

 

[Dave Hess]

dump it