diff --git a/artlib/common/BaseART.py b/artlib/common/BaseART.py
index 6e6abce..409816b 100644
--- a/artlib/common/BaseART.py
+++ b/artlib/common/BaseART.py
@@ -106,6 +106,45 @@ def set_params(self, **params):
         self.validate_params(local_params)
         return self
 
+    def set_data_bounds(self, lower_bounds: np.ndarray, upper_bounds: np.ndarray):
+        """Manually set the data bounds for normalization.
+
+        Parameters
+        ----------
+        lower_bounds : np.ndarray
+            The lower bounds for each column.
+
+        upper_bounds : np.ndarray
+            The upper bounds for each column.
+
+        """
+        if self.is_fitted_:
+            raise ValueError("Cannot change data limits after fit.")
+        self.d_min_ = lower_bounds
+        self.d_max_ = upper_bounds
+
+    def find_data_bounds(
+        self, *data_batches: list[np.ndarray]
+    ) -> Tuple[np.ndarray, np.ndarray]:
+        """Manually set the data bounds for normalization.
+
+        Parameters
+        ----------
+        *data_batches : list[np.ndarray]
+            Batches of data to be presented to the model
+
+        Returns
+        -------
+        tuple[np.ndarray, np.ndarray]
+            Lower and upper bounds for data.
+
+        """
+        all_data = np.vstack(data_batches)
+        lower_bounds = np.min(all_data)
+        upper_bounds = np.max(all_data)
+
+        return lower_bounds, upper_bounds
+
     def prepare_data(self, X: np.ndarray) -> np.ndarray:
         """Prepare data for clustering.
 
@@ -187,8 +226,23 @@ def validate_data(self, X: np.ndarray):
         - X: data set
 
         """
-        assert np.all(X >= 0), "Data has not been normalized"
-        assert np.all(X <= 1.0), "Data has not been normalized"
+        normalization_message = (
+            "Data has not been normalized or was not normalized "
+            "correctly. All values must fall between 0 and 1, "
+            "inclusively."
+        )
+        if self.is_fitted_:
+            normalization_message += (
+                "\nThis appears to not be the first batch of "
+                "data. Data boundaries must be calculated for "
+                "the entire data space. Prior to fitting, use "
+                "BaseART.set_data_bounds() to manually set the "
+                "bounds for your data or use "
+                "BaseART.find_data_bounds() to identify the "
+                "bounds automatically for multiple batches."
+            )
+        assert np.all(X >= 0), normalization_message
+        assert np.all(X <= 1.0), normalization_message
         self.check_dimensions(X)
 
     def category_choice(
diff --git a/unit_tests/test_FuzzyART.py b/unit_tests/test_FuzzyART.py
index e07c848..e4cd338 100644
--- a/unit_tests/test_FuzzyART.py
+++ b/unit_tests/test_FuzzyART.py
@@ -148,3 +148,66 @@ def test_clustering(art_model):
     labels = art_model.fit_predict(data)
 
     assert np.all(np.equal(labels, np.array([0, 0, 1, 2, 3])))
+
+
+def test_validate_data(art_model):
+    # Test validate_data with normalized data
+    X = np.array([[-0.1, 0.2], [1.1, 0.4]])
+    art_model.is_fitted_ = False
+    with pytest.raises(AssertionError):
+        art_model.validate_data(X)
+
+def test_validate_data_again(art_model):
+    # Test validate_data with normalized data
+    X = np.array([[0.1, 0.2], [0.3, 0.4]])
+    art_model.is_fitted_ = False
+    art_model.validate_data(X)  # Should pass without assertion error
+
+    # Test validate_data with data out of bounds
+    X_invalid = np.array([[-0.1, 0.2], [1.1, 0.4]])
+    with pytest.raises(AssertionError):
+        art_model.validate_data(X_invalid)
+
+
+def test_set_data_bounds(art_model):
+    # Test set_data_bounds with valid bounds
+    lower_bounds = np.array([0.0, 0.0])
+    upper_bounds = np.array([1.0, 1.0])
+    art_model.is_fitted_ = False
+    art_model.set_data_bounds(lower_bounds, upper_bounds)
+    assert np.all(art_model.d_min_ == lower_bounds)
+    assert np.all(art_model.d_max_ == upper_bounds)
+
+    # Test set_data_bounds after the model is fitted
+    art_model.is_fitted_ = True
+    with pytest.raises(ValueError, match="Cannot change data limits after fit."):
+        art_model.set_data_bounds(lower_bounds, upper_bounds)
+    X = np.array([[0.1, 0.2], [0.3, 0.4]])
+    X_norm = art_model.prepare_data(X)
+    assert np.all(X_norm == X)
+
+
+def test_find_data_bounds(art_model):
+    # Test find_data_bounds with multiple data batches
+    batch_1 = np.array([[0.1, 0.2], [0.3, 0.4]])
+    batch_2 = np.array([[0.0, 0.1], [0.5, 0.6]])
+    lower_bounds, upper_bounds = art_model.find_data_bounds(batch_1, batch_2)
+    np.testing.assert_array_equal(lower_bounds, np.array([0.0, 0.1]))
+    np.testing.assert_array_equal(upper_bounds, np.array([0.5, 0.6]))
+
+
+def test_prepare_data(art_model):
+    # Test prepare_data with valid data
+    X = np.array([[0.0, 0.5], [0.2, 1.0]])
+    art_model.d_min_ = np.array([0.0, 0.0])
+    art_model.d_max_ = np.array([1.0, 1.0])
+    normalized_X = art_model.prepare_data(X)
+    np.testing.assert_array_almost_equal(normalized_X, X)  # Already normalized
+
+    # Test prepare_data with data requiring normalization
+    X = np.array([[1.0, 10.0], [5.0, 20.0]])
+    art_model.d_min_ = np.array([1.0, 10.0])
+    art_model.d_max_ = np.array([5.0, 20.0])
+    normalized_X = art_model.prepare_data(X)
+    expected_normalized_X = np.array([[0.0, 0.0, 1.0, 1.0], [1.0, 1.0, 0.0, 0.0]])
+    np.testing.assert_array_almost_equal(normalized_X, expected_normalized_X)
\ No newline at end of file