SPE (Solid Polymer Electrolyte) and PEM (Proton Exchange Membrane) are the two main electrode technologies used in hydrogen water machines. Both produce molecular hydrogen through electrolysis, but they differ in how gases are separated and what types of water they produce. This guide explains the technical differences and helps you choose between a full water ioniser and a dedicated hydrogen generator.
SPE uses a solid polymer membrane as the electrolyte, replacing the liquid electrolyte solutions used in older designs. The Enagic LeveLuk K8 uses SPE technology with 8 platinum-coated titanium electrode plates to produce hydrogen-rich alkaline water at up to 1,200 ppb dissolved hydrogen and -800mV ORP.
PEM is a specific type of SPE where the membrane allows protons to pass while blocking gases. This enables full separation of hydrogen, oxygen, ozone, and chlorine — ensuring only pure hydrogen dissolves into the drinking water. PEM is commonly used in dedicated hydrogen water generators.