A system for forming a homogeneous mixture of slurry in the form of a suspension of discrete particles of chromatographic media in a liquid in a vessel containing said media, the system comprising: a tubular member in the form of a hand held rod, said tubular member comprising a first outer and second inner concentric tubes (20,30) wherein, said rod includes a) said first tube comprises an elongate body having a first distal orifice for entry of the liquid or the slurry therein and a second proximal orifice for exit of the liquid or the slurry therefrom; and b) said second tube comprising an elongate body having a first proximal port for entry of the liquid or the slurry therein and a second distal port for exit of the liquid or the slurry therefrom; the system further comprising a pump which is in fluid communication with a liquid reservoir and is connected by means of hosing to said first proximal port and to the second proximal orifice the system being characterised in that the pump is arranged to cause the liquid or the slurry to enter the first proximal port and exit the second distal port and also to draw in the liquid or the slurry from the first distal orifice and to exit the second proximal orifice, and in that said second distal port includes a nozzle and an end piece for spraying the liquid, wherein the angle between the end piece and the nozzle controls the direction of the spray of the liquid exiting from the second distal port of the inner tube, wherein the angle is configured to prevent liquid being aspirated into the first distal orifice of outer tube and wherein the nozzle is arranged to produce a radial spray of the liquid or the slurry directed at an angle of at least 90 degrees to the elongate body of the outer tube. a tubular member in the form of a hand held rod, said tubular member comprising a first outer and second inner concentric tubes (20,30) wherein, said rod includes a) said first tube comprises an elongate body having a first distal orifice for entry of the liquid or the slurry therein and a second proximal orifice for exit of the liquid or the slurry therefrom; and b) said second tube comprising an elongate body having a first proximal port for entry of the liquid or the slurry therein and a second distal port for exit of the liquid or the slurry therefrom; a) said first tube comprises an elongate body having a first distal orifice for entry of the liquid or the slurry therein and a second proximal orifice for exit of the liquid or the slurry therefrom; and b) said second tube comprising an elongate body having a first proximal port for entry of the liquid or the slurry therein and a second distal port for exit of the liquid or the slurry therefrom; the system further comprising a pump which is in fluid communication with a liquid reservoir and is connected by means of hosing to said first proximal port and to the second proximal orifice the system being characterised in that the pump is arranged to cause the liquid or the slurry to enter the first proximal port and exit the second distal port and also to draw in the liquid or the slurry from the first distal orifice and to exit the second proximal orifice, and in that said second distal port includes a nozzle and an end piece for spraying the liquid, wherein the angle between the end piece and the nozzle controls the direction of the spray of the liquid exiting from the second distal port of the inner tube, wherein the angle is configured to prevent liquid being aspirated into the first distal orifice of outer tube and wherein the nozzle is arranged to produce a radial spray of the liquid or the slurry directed at an angle of at least 90 degrees to the elongate body of the outer tube.