A method of producing bimodal ethylene-based polymer comprising: reacting ethylene monomer and C 3 -C 12 α-olefin comonomer in solvent in the presence of a first catalyst in an agitated solution polymerization reactor to produce a first polymer fraction; outputting effluent from the agitated solution polymerization reactor, wherein effluent comprises the first polymer fraction, unreacted ethylene monomer, and unreacted C 3 -C 12 α-olefin comonomer; adding a second catalyst to the effluent downstream of the agitated solution polymerization reactor and upstream from a non-agitated solution polymerization reactor, wherein the second catalyst facilitates further reaction of the unreacted ethylene monomer and unreacted C 3 -C 12 α-olefin comonomer to produce a second polymer fraction having a density and melt index (I 2 ) different from the first polymer fraction and the second catalyst and effluent mix in at least one mixer downstream from the agitated solution polymerization reactor and upstream of the non-agitated solution polymerization reactor; passing the second catalyst, second polymer fraction, and the first polymer fraction to the non-agitated solution polymerization reactor; and passing additional ethylene monomer, additional C 3 -C 12 α-olefin comonomer, and solvent to the non-agitated solution polymerization reactor, wherein the additional ethylene monomer, additional C 3 -C 12 α-olefin comonomer react in the presence of the second catalyst to produce more second polymer fraction and thereby the bimodal ethylene-based polymer, the bimodal ethylene-based polymer comprising the first polymer fraction and the second polymer fraction. reacting ethylene monomer and C 3 -C 12 α-olefin comonomer in solvent in the presence of a first catalyst in an agitated solution polymerization reactor to produce a first polymer fraction; outputting effluent from the agitated solution polymerization reactor, wherein effluent comprises the first polymer fraction, unreacted ethylene monomer, and unreacted C 3 -C 12 α-olefin comonomer; adding a second catalyst to the effluent downstream of the agitated solution polymerization reactor and upstream from a non-agitated solution polymerization reactor, wherein the second catalyst facilitates further reaction of the unreacted ethylene monomer and unreacted C 3 -C 12 α-olefin comonomer to produce a second polymer fraction having a density and melt index (I 2 ) different from the first polymer fraction and the second catalyst and effluent mix in at least one mixer downstream from the agitated solution polymerization reactor and upstream of the non-agitated solution polymerization reactor; passing the second catalyst, second polymer fraction, and the first polymer fraction to the non-agitated solution polymerization reactor; and passing additional ethylene monomer, additional C 3 -C 12 α-olefin comonomer, and solvent to the non-agitated solution polymerization reactor, wherein the additional ethylene monomer, additional C 3 -C 12 α-olefin comonomer react in the presence of the second catalyst to produce more second polymer fraction and thereby the bimodal ethylene-based polymer, the bimodal ethylene-based polymer comprising the first polymer fraction and the second polymer fraction. <EOS>