Hi guys. I noticed my trident started coasting away from its usual numbers so I verified with my Hanna Checker. Numbers were a little off so I recalibrated using the Hanna results as a reference. I noticed with the next test the trident does, my numbers swing completely out of wack again. I tried priming and resetting all lines and recalibrating again. Then boom, the next test the numbers are all out of wack again. What can be wrong?