Hello guys, I have a nit picky possibly over thinking question. First of all I live up in Northern usa where I see negative Temps in the winter and 95 degree Summer days. My concern and question is, when i am flushing my coolant system with water, and I drain all of the water I flushed my system with from the radiator to prepare my final stage of the process of adding my 50/50 mix of coolant, how do I know that I got all of the straight water out of the system in the first place ??? Something tells me I'll never be able to get all that straight water out of my coolant system... so this means my coolant mixture will inevitably be less than 50/50 mix, which is not good for me when it's -15 degrees outside... those of you who have done flushes, how the heck do you know you got all the water out? How do you compensate?