We recommend 100% serum or HEPES buffered HBSS.
The sorter uses PBS as its sheath fluid. Mixing large quantities of PBS with buffer containing calcium chloride may produce a precipitate if calcium phosphate on the cell membranes. This can adversely affect viability. For this reason, it is preferable to sort large numbers of cells into 100% serum, and not into regular culture medium. HEPES buffered HBSS without calcium is an alternative. If you must sort into medium, remember that the pH will rise with time, and it’s best to start with it on the acid side of neutral.