Another vote for EDT.
Now 2oz is the performance dose - having a 33 gallon tank, its somewhat hard to do exact math. So I have been using 4 oz for 33 gallon tank. 4 oz is performance dose for about 50 gallons of fuel - and I usually refill diesel when I have quarter tank left.
So my leftover 1/4 tank is treated fuel - and then I add 4 oz EDT to about 25 gallon fuel - I changed my first Fuel Filter myself at 15K miles, and there was about a cup of water in the fuel filter. I guess the EDT is doing its job !
I emailed EDT, and they said that 4oz at fill-ups should NOT harm/hurt the engine - I read online that it can clog the filters, but the manufacturer said it wont harm the motor and that its helping separate the water BEFORE it gets to my engine - which is true, because water in engine would be bad !
Open to hear thoughts/criticism - yes I am using more than recommended treatment, the cost is not an issue to me, so even if I am "wasting" extra, thats fine by me. I am only interested in knowing if it is harmful in any way.