Load the two Neodols into the vessel and mix. Add the sodium xylene sulfonate solution and mix. Add the water and EDTA salt, either premixed or in that order. Mix until homogeneous. Notes: Heating the water and/or Neodols to 100-120 F before addition will facilitate solution, but is not essential. pH on all samples is approximately 10, due to presence of the highly alkaline EDTA salt used. If a lower pH, e.g., 7-7.5, is preferable, this can be obtained by using the appropriate EDTA salt and/or neutralizing with NaHSO4.