I got this off of ebay:
http://www.ebay.com/itm/122019620741?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
It adjust the PH due to temps. Easy one button calibration. Just need to buy the calibration fluid. You can make storage solution by adding a little table salt to the PH...