Buffers Tris (1 M, pH 7.5) Tris (1 M, pH 7.5) Tris recipe for buffering V. fischeri growth media. Amount Reagent 127 g Tris-HCl 23.6 g Tris base Stir until dissolved, adjust to pH 7.5, then adjust volume to 1L with dI H2O. Filter-sterilize and store at room temperature.