Unscrew the bottom cap from the outer body.
Check that the membrane cartridge is seated properly into the bottom cap by pushing on the cartridge using the tool provided.
Invert the outer body and check that there is inner filling solution inside the center chamber. Using the syringe provided, fill the center chamber with inner filling solution if necessary.
Place the bottom cap onto the outer body threads and screw the bottom cap onto the outer body until fingertight.Check that the assembled cap is not leaking at the bottom of the electrode or else repeat the above steps.
Lower the rubber insert covering the filling hole of the reference chamber to expose the fill hole. Fill the combination electrode with the reference filling solution shipped with the electrode to a level just below the fill hole.
Gently shake the electrode downward in the same manner as a clinical thermometer to remove any air bubbles which might be trapped behind the fluoride membrane. Immerse the fluoride electrode in fluoride standard for thirty minutes. The electrode is now ready for use.