diff --git a/src/flownet/ahm/_run_ahm.py b/src/flownet/ahm/_run_ahm.py
index 0a769ac63..4d725903b 100644
--- a/src/flownet/ahm/_run_ahm.py
+++ b/src/flownet/ahm/_run_ahm.py
@@ -36,12 +36,6 @@ def _find_training_set_fraction(
     training_set_fraction = 1.0
 
     if config.flownet.training_set_end_date is not None:
-        if config.flownet.training_set_fraction is not None:
-            print(
-                "\nTraining set fraction and training set end date are both defined in config file.\n"
-                "The input given for training set fraction will be ignored.\n"
-                "The training set end date will be used to calculate the training set fraction.\n"
-            )
         if (
             not schedule.get_first_date()
             <= config.flownet.training_set_end_date
diff --git a/src/flownet/config_parser/_config_parser.py b/src/flownet/config_parser/_config_parser.py
index 5c2d873ae..2c72c6526 100644
--- a/src/flownet/config_parser/_config_parser.py
+++ b/src/flownet/config_parser/_config_parser.py
@@ -344,7 +344,7 @@ def create_schema(_to_abs_path) -> Dict:
                         MK.Type: types.NamedDict,
                         MK.Content: {
                             "scheme": {MK.Type: types.String, MK.Default: "global"},
-                            "datum_depth": {MK.Type: types.Number},
+                            "datum_depth": {MK.Type: types.Number, MK.AllowNone: True},
                             "datum_pressure": {
                                 MK.Type: types.NamedDict,
                                 MK.Content: {
@@ -518,4 +518,10 @@ def _to_abs_path(path: Optional[str]) -> str:
         ):
             raise ValueError(f"The input case {suffix} file does not exist")
 
+    if config.flownet.training_set_end_date and config.flownet.training_set_fraction:
+        raise ValueError(
+            "Ambiguous configuration input: 'training_set_fraction' and 'training_set_end_date' are "
+            "both defined in the configuration file."
+        )
+
     return config
diff --git a/tests/configs/norne_parameters.yml b/tests/configs/norne_parameters.yml
index a103011b3..9380b3872 100644
--- a/tests/configs/norne_parameters.yml
+++ b/tests/configs/norne_parameters.yml
@@ -10,7 +10,6 @@ flownet:
   random_seed: 999
   perforation_handling_strategy: bottom_point
   fast_pyscal: True
-  training_set_fraction: 0.7 # Fraction of observations (from 0 to 1) to use as training data
   training_set_end_date: 2005-01-31 #YYYY-MM-DD. If defined training set fraction is calculated from this date
   fault_tolerance: 0.1