I tested my Polder today by inserting it into a glass of crushed ice & water... it registered 28 degrees. Estimating it is about 5 degrees off, I would like to calibrate it, hence my question: Does anyone know how to calibrate the Polder single probe unit? It is the standard model that Amazon sells for $20. I read the directions, and just don't see any mention of calibration. Any help is apreciated.