Abstract: A pH sensor including a reference electrode, a measuring electrode operatively connected to said reference electrode, a fluid conduit for containing an electrolyte in electrolytic contact with said reference electrode, a reservoir in fluid communication with said fluid conduit, a reference junction encasing said reference electrode, and an external junction, wherein said electrolyte comprises a viscous silica suspension to maintain a flow of said electrolyte from said reservoir to reduce inward diffusion through said external junction.