I personally would soak it first, then check it in a calibration solution.
It seems mine has dried out between grow seasons and that's all I do. It's not hannah, but its still the same concept.

The last one we bought arrived dry with foam glued to it. Probly dried up sitting on shelf at wholesalers. Soaked it and cleaned off bulb with toothbrush and have kept it wet ever since. Two years with no problems. Think it's best to do that like manufactures recommend. I use it daily and swish it in tap water then RO then the nutes I'm measuring. When we finish it's stuck back in storage solution after the cleaning swishes in tap and RO. This one is an HM PH-200 and we are very happy with it's preformance. Looks just like the Sunleaves Expert Plus we have seen in the catalogs.