Previously it had been observed that crystals tend to form either at the inlet or outlet of the cell, or, if connected, at the end of tubes. To ensure higher reproducibility, the inlet and outlet tubes were truncated at a length of 3 cm and the ends sealed with parafilm to avoid evaporation of the sample. It would also have been possible to do without tubes, however, due to the small size of the crystallisation cell and the need to seal the inlet and outlet, this often introduced air bubbles so that it was decided to use tubes of a constant length instead.