diff --git a/src/hope_dedup_engine/apps/faces/utils/duplication_detector.py b/src/hope_dedup_engine/apps/faces/utils/duplication_detector.py
index d7292267..5d9fad5b 100644
--- a/src/hope_dedup_engine/apps/faces/utils/duplication_detector.py
+++ b/src/hope_dedup_engine/apps/faces/utils/duplication_detector.py
@@ -43,7 +43,8 @@ def __init__(self, filename: str) -> None:
         self.filename: str = filename
         self.encodings_filename: str = f"{self.filename}.npy"
         self.scale_factor: float = config.SCALE_FACTOR
-        self.mean_values: Tuple[float, float, float] = tuple(map(float, config.MEAN_VALUES.split(",")))
+        # self.mean_values: Tuple[float, float, float] = tuple(map(float, config.MEAN_VALUES.split(", ")))
+        self.mean_values: Tuple[float, float, float] = config.MEAN_VALUES
         self.face_detection_confidence: float = config.FACE_DETECTION_CONFIDENCE
         self.face_detection_model: str = config.FACE_DETECTION_MODEL
         self.distance_threshold: float = config.DISTANCE_THRESHOLD
diff --git a/src/hope_dedup_engine/apps/faces/validators.py b/src/hope_dedup_engine/apps/faces/validators.py
new file mode 100644
index 00000000..893275ba
--- /dev/null
+++ b/src/hope_dedup_engine/apps/faces/validators.py
@@ -0,0 +1,24 @@
+from django.forms import CharField, ValidationError
+
+
+class MeanValuesTupleField(CharField):
+    def to_python(self, value):
+        try:
+            values = tuple(map(float, value.split(", ")))
+            if len(values) != 3:
+                raise ValueError("The tuple must have exactly three elements.")
+            if not all(-255 <= v <= 255 for v in values):
+                raise ValueError("Each value in the tuple must be between -255 and 255.")
+            return values
+        except Exception as e:
+            raise ValidationError(
+                """
+                Enter a valid tuple of three float values separated by commas and spaces, e.g. '0.0, 0.0, 0.0'.
+                Each value must be between -255 and 255.
+                """
+            ) from e
+
+    def prepare_value(self, value):
+        if isinstance(value, tuple):
+            return ", ".join(map(str, value))
+        return value
diff --git a/src/hope_dedup_engine/config/fragments/constance.py b/src/hope_dedup_engine/config/fragments/constance.py
index 0fa1a04d..b3852113 100644
--- a/src/hope_dedup_engine/config/fragments/constance.py
+++ b/src/hope_dedup_engine/config/fragments/constance.py
@@ -4,13 +4,6 @@
 
 CONSTANCE_BACKEND = "constance.backends.database.DatabaseBackend"
 
-CONSTANCE_ADDITIONAL_FIELDS = {
-    "email": [
-        "django.forms.EmailField",
-        {},
-    ],
-}
-
 CONSTANCE_CONFIG = {
     "NEW_USER_IS_STAFF": (False, "Set any new user as staff", bool),
     "NEW_USER_DEFAULT_GROUP": (DEFAULT_GROUP_NAME, "Group to assign to any new user", str),
@@ -102,6 +95,10 @@
 }
 
 CONSTANCE_ADDITIONAL_FIELDS = {
+    "email": [
+        "django.forms.EmailField",
+        {},
+    ],
     "dnn_backend": [
         "django.forms.ChoiceField",
         {
@@ -120,10 +117,5 @@
             "choices": (("hog", "HOG"), ("cnn", "CNN")),
         },
     ],
-    "tuple_field": [
-        "django.forms.CharField",
-        {
-            "widget": "django.forms.TextInput",
-        },
-    ],
+    "tuple_field": ["hope_dedup_engine.apps.faces.validators.MeanValuesTupleField", {}],
 }