Hydraulic conveying is similar to pneumatic conveying, but uses a liquid rather than a gas as the carrier fluid. The smaller difference in specific gravity between the particles and carrier fluid makes it easier to entrain solids, but it is much harder to separate the solids from the carrier. Because pumps are less susceptible to damage by solids than compressors, hydraulic conveying systems usually mix the solid and liquid upstream of the pump and then pump the resulting slurry