A method for automatically without any required manual interaction packing a media bed in a column (3) from a slurry being a dispersion of said media particles and a liquid, said method comprising the steps a)-f) which all are performed automatically: a) filling the column (3) with a certain volume of slurry; b) packing a media bed from the slurry to a predefined target bed height or a predefined target bed compression; c) testing the separation efficiency of the packed bed; d) automatically unpacking the bed if test results not are acceptable or alternatively flow conditioning the packed bed if test results not are acceptable and return to c); e) calculating new volume of slurry to be filled into the column based on the test results; f) repeat from a).