diff --git a/Project.toml b/Project.toml
index bbadcc44..fc805cc5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ClimaCalibrate"
 uuid = "4347a170-ebd6-470c-89d3-5c705c0cacc2"
 authors = ["Climate Modeling Alliance"]
-version = "0.0.4"
+version = "0.0.5"
 
 [deps]
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
diff --git a/src/backends.jl b/src/backends.jl
index 1d01d19b..fc1c90cc 100644
--- a/src/backends.jl
+++ b/src/backends.jl
@@ -1,5 +1,7 @@
 using Distributed
 
+import EnsembleKalmanProcesses as EKP
+
 export get_backend, calibrate, model_run
 
 abstract type AbstractBackend end
@@ -82,10 +84,15 @@ function calibrate(
     ::Type{JuliaBackend},
     config::ExperimentConfig;
     reruns = 0,
+    ekp = nothing,
     ekp_kwargs...,
 )
     (; n_iterations, output_dir, ensemble_size) = config
-    eki = initialize(config; ekp_kwargs...)
+    ekp = if ekp isa EKP.EnsembleKalmanProcess
+        initialize(ekp, prior, output_dir)
+    else
+        initialize(config; ekp_kwargs...)
+    end
     on_error(e::InterruptException) = rethrow(e)
     on_error(e) =
         @error "Single ensemble member has errored. See stacktrace" exception =
@@ -101,14 +108,15 @@ function calibrate(
         terminate = update_ensemble(config, i)
         !isnothing(terminate) && break
         iter_path = path_to_iteration(output_dir, i + 1)
-        eki = JLD2.load_object(joinpath(iter_path, "eki_file.jld2"))
+        ekp = JLD2.load_object(joinpath(iter_path, "eki_file.jld2"))
     end
-    return eki
+    return ekp
 end
 
 """
     calibrate(::Type{AbstractBackend}, config::ExperimentConfig; kwargs...)
     calibrate(::Type{AbstractBackend}, experiment_dir; kwargs...)
+    calibrate(::Type{AbstractBackend}, ekp::EnsembleKalmanProcess, experiment_dir; kwargs...)
 
 Run a full calibration, scheduling the forward model runs on Caltech's HPC cluster.
 
@@ -160,13 +168,18 @@ function calibrate(
     ),
     verbose = false,
     reruns = 1,
+    ekp = nothing,
     hpc_kwargs,
     ekp_kwargs...,
 )
-    (; n_iterations, output_dir, ensemble_size) = config
+    (; n_iterations, output_dir, prior, ensemble_size) = config
     @info "Initializing calibration" n_iterations ensemble_size output_dir
 
-    eki = initialize(config; ekp_kwargs...)
+    ekp = if ekp isa EKP.EnsembleKalmanProcess
+        initialize(ekp, prior, output_dir)
+    else
+        initialize(config; ekp_kwargs...)
+    end
     module_load_str = module_load_string(b)
     for i in 0:(n_iterations - 1)
         @info "Iteration $i"
@@ -201,9 +214,9 @@ function calibrate(
         terminate = update_ensemble(config, i)
         !isnothing(terminate) && break
         iter_path = path_to_iteration(output_dir, i + 1)
-        eki = JLD2.load_object(joinpath(iter_path, "eki_file.jld2"))
+        ekp = JLD2.load_object(joinpath(iter_path, "eki_file.jld2"))
     end
-    return eki
+    return ekp
 end
 
 # Dispatch on backend type to unify `calibrate` for all HPCBackends
diff --git a/src/ekp_interface.jl b/src/ekp_interface.jl
index 889ab714..a9625893 100644
--- a/src/ekp_interface.jl
+++ b/src/ekp_interface.jl
@@ -268,10 +268,11 @@ function _initialize(
     initial_ensemble =
         EKP.construct_initial_ensemble(rng_ekp, prior, ensemble_size)
 
+    ekp_str_kwargs = Dict([string(k) => v for (k, v) in ekp_kwargs])
     eki_constructor =
         (args...) -> EKP.EnsembleKalmanProcess(
             args...,
-            Dict(EKP.default_options_dict(EKP.Inversion())..., ekp_kwargs...);
+            merge(EKP.default_options_dict(EKP.Inversion()), ekp_str_kwargs);
             rng = rng_ekp,
         )
 
diff --git a/test/Project.toml b/test/Project.toml
index 0b7abcc4..535d6ec8 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -1,6 +1,5 @@
 [deps]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
-CalibrateEmulateSample = "95e48a1f-0bec-4818-9538-3db4340308e3"
 ClimaCalibrate = "4347a170-ebd6-470c-89d3-5c705c0cacc2"
 ClimaParams = "5c42b081-d73a-476f-9059-fd94b934656c"
 Conda = "8f4d0f93-b110-5947-807f-2305c1781a2d"
@@ -12,3 +11,6 @@ Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[compat]
+EnsembleKalmanProcesses = "2"
diff --git a/test/ekp_interface.jl b/test/ekp_interface.jl
index 9c95785d..088696b7 100644
--- a/test/ekp_interface.jl
+++ b/test/ekp_interface.jl
@@ -31,7 +31,19 @@ config = CAL.ExperimentConfig(
     output_dir,
 )
 
-eki = CAL.initialize(config)
+
+user_initial_ensemble =
+    EKP.construct_initial_ensemble(rng_ekp, prior, ensemble_size)
+user_constructed_eki = EKP.EnsembleKalmanProcess(
+    user_initial_ensemble,
+    observations,
+    noise,
+    EKP.Inversion(),
+    EKP.default_options_dict(EKP.Inversion());
+    rng = rng_ekp,
+)
+
+eki = CAL.initialize(config; rng_seed)
 eki_with_kwargs = CAL.initialize(
     config;
     scheduler = EKP.MutableScheduler(2),
@@ -46,6 +58,14 @@ eki_with_kwargs = CAL.initialize(
     @test eki_with_kwargs.accelerator isa EKP.NesterovAccelerator
 end
 
+@testset "Test that a user-constructed EKP obj is same as initialized one" begin
+    for prop in propertynames(eki)
+        prop in [:u, :accelerator, :localizer] && continue
+        @test getproperty(eki, prop) == getproperty(user_constructed_eki, prop)
+    end
+    @test eki.u[1].stored_data == user_constructed_eki.u[1].stored_data
+end
+
 override_file = joinpath(
     config.output_dir,
     "iteration_000",
@@ -80,11 +100,10 @@ end
         joinpath(output_dir, "iteration_000", "member_001", "parameters.toml")
     td = CP.create_toml_dict(FT; override_file)
     params = CP.get_parameter_values(td, param_names)
-    @test params.one == 2.513110562120818
-    @test params.two == 4.614950047803855
+    @test params.one == 3.1313341622997677
+    @test params.two == 5.063035177034372
 end
 
-
 @testset "Environment variables" begin
     @test_throws ErrorException(
         "Experiment dir not found in environment. Ensure that env variable \"CALIBRATION_EXPERIMENT_DIR\" is set.",
diff --git a/test/pure_julia_e2e.jl b/test/pure_julia_e2e.jl
index 1e330392..f2698a10 100644
--- a/test/pure_julia_e2e.jl
+++ b/test/pure_julia_e2e.jl
@@ -77,7 +77,7 @@ ekp = calibrate(JuliaBackend, experiment_config)
     parameter_values =
         [EKP.get_ϕ_mean(prior, ekp, it) for it in 1:(n_iterations + 1)]
     @test parameter_values[1][1] ≈ 8.507 rtol = 0.01
-    @test parameter_values[end][1] ≈ 19.0124 rtol = 0.01
+    @test parameter_values[end][1] ≈ 11.852161842745355 rtol = 0.01
 end
 
 rm(output_dir; recursive = true)
diff --git a/test/runtests.jl b/test/runtests.jl
index abc513c5..1be7ad68 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -2,6 +2,7 @@ using Test
 
 include("ekp_interface.jl")
 include("model_interface.jl")
-include("emulate_sample.jl")
+# Disabled since we use EKP 2.0 in testing, CES is still incompatible with EKP 2.0
+# include("emulate_sample.jl")
 include("pure_julia_e2e.jl")
 include("aqua.jl")