Fluid separation assembly that allows easy and fast change-out even in confined spaces, and also minimizes or eliminates leakage during change-out. A fluid separation unit having a housing containing separation means, the housing having an inlet and an outlet spaced from the inlet, each including a fitting for attachment of the housing to a manifold or other device allowing fluid communication through the separation means to a point of use is provided. The fittings are designed for quick connect/disconnect, and for minimal or no leakage. The fittings may be on opposite ends, with top and bottom fittings of different configurations, thereby ensuring proper installation of the assembly. The particular medium to be separated is not particularly limited, and can include slurries, fluids including water, and pre-loaded chromatography columns.