The Department of Energy selected CSSX as the preferred cesium removal technology for Savannah River Site waste. As a pretreatment step for the CSSX flowsheet, personnel contact the incoming salt solution that contains entrained sludge with MST to adsorb strontium and select actinides. They filter the resulting slurry to remove the sludge and MST. The filtrate receives further treatment to remove cesium in the solvent extraction system. The baseline filtration technology uses a Mott crossflow filter. We conducted pilot-scale crossflow filter testing with simulated SRS high level waste to evaluate the impact of operating parameters on the crossflow filtration process. The tests employed 0.5 micron and 0.1 micron filters. The feed slurries for these tests included simulated sludge plus MST, simulated sludge only, and simulated sludge plus manganese oxide solids. The supernate for these tests consisted of 5.6-6.4 M sodium, average salt solution. During the tests, we measured the axial pressure drop as a function of axial velocity, feed slurry, and insoluble solids concentration. This report documents the axial pressure drop data.