[thoughtful]

FIRST suggests that the POT should not be more than a 100k Ohms. Yours is 10 times more, i would suggest that you use a 100K one. Too much resistance in the circuit will come out as a value of 0 voltage to the RC. As in, if there is only 0.5 volts flowing through the RC then it reads it as 0 Volts. It is a good idea to stay near the 100 K mark.