diff --git a/grid_apps-assets/uijson/grid_model_merger.ui.json b/grid_apps-assets/uijson/grid_model_merger.ui.json
index 99c3afe..c7c2e8e 100644
--- a/grid_apps-assets/uijson/grid_model_merger.ui.json
+++ b/grid_apps-assets/uijson/grid_model_merger.ui.json
@@ -47,8 +47,7 @@
             "Cell"
         ],
         "dataType": [
-            "Float",
-            "Integer"
+            "Float"
         ],
         "group": "Input A",
         "main": true,
@@ -77,8 +76,7 @@
             "Cell"
         ],
         "dataType": [
-            "Float",
-            "Integer"
+            "Float"
         ],
         "group": "Input B",
         "main": true,
@@ -107,8 +105,7 @@
             "Cell"
         ],
         "dataType": [
-            "Float",
-            "Integer"
+            "Float"
         ],
         "group": "Input C",
         "main": true,
@@ -137,8 +134,7 @@
             "Cell"
         ],
         "dataType": [
-            "Float",
-            "Integer"
+            "Float"
         ],
         "group": "Input D",
         "main": true,
@@ -167,8 +163,7 @@
             "Cell"
         ],
         "dataType": [
-            "Float",
-            "Integer"
+            "Float"
         ],
         "group": "Input E",
         "main": true,
@@ -197,8 +192,7 @@
             "Cell"
         ],
         "dataType": [
-            "Float",
-            "Integer"
+            "Float"
         ],
         "group": "Input F",
         "main": true,
diff --git a/grid_apps/grid_model_merger/driver.py b/grid_apps/grid_model_merger/driver.py
index 92eb3a8..38775a2 100644
--- a/grid_apps/grid_model_merger/driver.py
+++ b/grid_apps/grid_model_merger/driver.py
@@ -210,12 +210,21 @@ def interpolate_models_to_output_grid(self):
                 )
                 weights = np.nansum([weights, cell_weights], axis=0)
 
+            if not np.any(weights > 0):
+                logger.warning(
+                    "No valid model values found in any selection. No output model will be created."
+                )
+                return
+
             # Normalizes weighted sum
             non_zero = weights > 0
             out_model[non_zero] /= weights[non_zero]
             out_model[~non_zero] = np.nan
 
-            if self.params.scaling_type == ScalingTypeEnum.LOG:
+            if (
+                self.params.scaling_type == ScalingTypeEnum.LOG
+                and threshold is not None
+            ):
                 out_model = inv_symlog(out_model, threshold=threshold)
 
             if np.any(~np.isnan(out_model)):
diff --git a/grid_apps/utils.py b/grid_apps/utils.py
index 05e9343..78e05fb 100644
--- a/grid_apps/utils.py
+++ b/grid_apps/utils.py
@@ -295,8 +295,13 @@ def refine_tree_by_mesh(
 
     elif isinstance(mesh, Grid2D):
         centers = mesh.centroids
-        octree_level = np.max(
-            [0, int(np.min([mesh.u_cell_size, mesh.v_cell_size]) // np.min(tree.h)) - 1]
+        octree_level = np.maximum(
+            0,
+            int(
+                np.min([mesh.u_cell_size, mesh.v_cell_size])
+                // np.min(np.hstack(tree.h[:2]))
+            )
+            - 1,
         )
         levels = np.full(mesh.n_cells, tree.max_level - octree_level, dtype=int)
 
diff --git a/tests/run_tests/grid_model_merger_test.py b/tests/run_tests/grid_model_merger_test.py
index 0f3e44b..35db3b5 100644
--- a/tests/run_tests/grid_model_merger_test.py
+++ b/tests/run_tests/grid_model_merger_test.py
@@ -9,6 +9,7 @@
 
 from __future__ import annotations
 
+import logging
 from pathlib import Path
 
 import numpy as np
@@ -112,6 +113,27 @@ def test_merge_block_model(tmp_path: Path):  # pylint: disable=too-many-locals
         np.testing.assert_almost_equal(merged_model.values[3406], 2.0, decimal=1)
 
 
+def test_merge_all_nan(tmp_path: Path, caplog):  # pylint: disable=too-many-locals
+
+    with Workspace.create(tmp_path / f"{__name__}.geoh5") as ws:
+        mesh = setup_block_model(ws)
+        model_a = mesh.add_data({"values": {"values": np.full(mesh.n_cells, np.nan)}})
+
+        options = GridModelMergerOptions.build(
+            {
+                "geoh5": ws,
+                "input_a_grid": mesh,
+                "input_a_model": model_a,
+            }
+        )
+
+        driver = Driver(options)
+        with caplog.at_level(logging.WARNING):
+            driver.run()
+
+        assert "No valid model values found" in caplog.text
+
+
 def test_merge_grid2d_model(tmp_path: Path):  # pylint: disable=too-many-locals
 
     with Workspace.create(tmp_path / f"{__name__}.geoh5") as ws: