I filled the resevior up with straight coolant, I figure when the engine starts and it starts to circulate through the motor the coolant level in the resevior will drop, I will just add the water then, which should give me a pretty good mix of coolant/water, I do have a coolant tester here I can check it with, looking for about 70% coolant which according to what I have read will give me protection from -64 to 140 degree's, so, that should work!