Hi after receiving my kh director at the end of November, I installed it yesterday - but I have a small issue - one of the final steps is to calibrate the pH probe - it will not calibrate - just immediately comes up with an error 'calibration failed. Please try again' - I've tried this several times all with the same result. I have double and triple checked the bnc connector is properly seated. The probe was still in its packing fluid when I received it. Could the probe be faulty?