I hadn’t thought about an electric one I use DD salinity refractometer and calibrate it with 35ppt solution everytime I use it, never had any issues, but I love gadgets... do they need to be kept damp at all times like the Hanna Ph tester does... as I’ve killed 2 of those letting the probes dry out....I read somewhere that it should stay calibrated for 30 days and it comes with 3 packets of 35 standard. This to me would just be an easier way to check alkalinity especially when mixing new water.