diff --git a/config/model_configs/diagnostic_edmfx_bomex_stretched_box.yml b/config/model_configs/diagnostic_edmfx_bomex_stretched_box.yml
index a49bb7a691..d983c5fcfb 100644
--- a/config/model_configs/diagnostic_edmfx_bomex_stretched_box.yml
+++ b/config/model_configs/diagnostic_edmfx_bomex_stretched_box.yml
@@ -17,16 +17,16 @@ edmfx_sgs_diffusive_flux: true
 moist: "equil"
 config: "box" 
 hyperdiff: "true" 
-kappa_4: 1e12
-x_max: 1e5 
-y_max: 1e5 
+kappa_4: 1e21
+x_max: 1e8 
+y_max: 1e8 
 x_elem: 2 
 y_elem: 2 
 z_elem: 30 
 z_max: 3e3 
 dz_bottom: 50.0
 dz_top: 200.0
-dt: "50secs" 
+dt: "200secs" 
 t_end: "6hours" 
 dt_save_to_disk: "10mins"
 toml: [toml/diagnostic_edmfx_box.toml]
diff --git a/config/model_configs/diagnostic_edmfx_rico_box.yml b/config/model_configs/diagnostic_edmfx_rico_box.yml
index 27f8412e47..dfa7ef529e 100644
--- a/config/model_configs/diagnostic_edmfx_rico_box.yml
+++ b/config/model_configs/diagnostic_edmfx_rico_box.yml
@@ -4,6 +4,8 @@ subsidence: Rico
 ls_adv: Rico
 surface_setup: Rico
 turbconv: diagnostic_edmfx
+implicit_diffusion: true
+approximate_linear_solve_iters: 2
 prognostic_tke: true
 edmfx_upwinding: first_order
 edmfx_entr_model: "Generalized" 
@@ -15,15 +17,15 @@ moist: equil
 precip_model: "0M"
 config: box
 hyperdiff: "true"
-kappa_4: 1e12
-x_max: 1e5
-y_max: 1e5
+kappa_4: 1e21
+x_max: 1e8
+y_max: 1e8
 x_elem: 2
 y_elem: 2
 z_elem: 100
 z_max: 4e3
 z_stretch: false
-dt: 10secs
+dt: 200secs
 t_end: 8hours
 dt_save_to_disk: 10mins
 toml: [toml/diagnostic_edmfx_trmm_box.toml]
diff --git a/config/model_configs/diagnostic_edmfx_trmm_box.yml b/config/model_configs/diagnostic_edmfx_trmm_box.yml
index 22a0cfd221..14608d7637 100644
--- a/config/model_configs/diagnostic_edmfx_trmm_box.yml
+++ b/config/model_configs/diagnostic_edmfx_trmm_box.yml
@@ -3,6 +3,8 @@ initial_condition: TRMM_LBA
 rad: TRMM_LBA
 surface_setup: TRMM_LBA
 turbconv: diagnostic_edmfx
+implicit_diffusion: true
+approximate_linear_solve_iters: 2
 prognostic_tke: true
 edmfx_upwinding: first_order
 edmfx_entr_model: "Generalized" 
@@ -16,15 +18,15 @@ precip_model: "0M"
 override_τ_precip: false
 config: box
 hyperdiff: "true"
-kappa_4: 1e12
-x_max: 1e5
-y_max: 1e5
+kappa_4: 1e21
+x_max: 1e8
+y_max: 1e8
 x_elem: 2
 y_elem: 2
 z_elem: 82
 z_max: 16400
 z_stretch: false
-dt: 10secs
+dt: 600secs
 t_end: 6hours
 dt_save_to_disk: 10mins
 FLOAT_TYPE: "Float64"
diff --git a/toml/diagnostic_edmfx_trmm_box.toml b/toml/diagnostic_edmfx_trmm_box.toml
index f9d2682fec..e7b12df4ed 100644
--- a/toml/diagnostic_edmfx_trmm_box.toml
+++ b/toml/diagnostic_edmfx_trmm_box.toml
@@ -1,6 +1,6 @@
 [precipitation_timescale]
 alias = "τ_precip"
-value = 100
+value = 600
 type = "float"
 
 [entr_tau]