The electromagnetic (EMCal) and hadronic (HCal) calorimeters for the sPHENIX
experiment will use about 100,000 silicon photomultipliers (SiPMs) as optical sensors (Hamamatsu S12572-33-015P). The effects of radiation damage in SiPMs from gamma rays has been measured and compared with the damage produced by neutrons. We have designed and constructed an automated SiPM testing device that measures the breakdown voltage and gain curve with the IV scan and SPS (single photon spectrum) method. It is being used to characterize SiPMs for the sPHENIX calorimeters and to prepare a database for SiPM sorting. We will report on the first months of operational experience, including precision, stability and reproducibility of the measurements, consistency with the available factory data, and the projected effect of the SiPMs on the overall calorimeter performance in sPHENIX.