A process for preparing a mixed catalyst compound used in the polymerization of polyolefins to produce bimodal polyethylenes is disclosed. In an embodiment, a process of preparing the mixed catalyst system includes: mixing a first catalyst and an activator in a first liquid medium to form a first mixture, combining a support with the first mixture to form a first support slurry, drying the first support slurry in an extent sufficient to provide a dried supported first catalyst, mixing the dried supported first catalyst in a second liquid medium to form a second support slurry, and combining one or more additional catalysts with the second support slurry to provide the mixed catalyst compound.