diff --git a/phygnn/layers/custom_layers.py b/phygnn/layers/custom_layers.py
index c640ae8..712994a 100644
--- a/phygnn/layers/custom_layers.py
+++ b/phygnn/layers/custom_layers.py
@@ -12,7 +12,7 @@ class FlexiblePadding(tf.keras.layers.Layer):
     """Class to perform padding on tensors
     """
 
-    def __init__(self, paddings, mode='REFLECT'):
+    def __init__(self, paddings, mode='REFLECT', option='tf'):
         """
         Parameters
         ----------
@@ -21,13 +21,30 @@ def __init__(self, paddings, mode='REFLECT'):
             rank of the tensor and elements give the number
             of leading and trailing pads
         mode : str
-            tf.pad() padding mode. Can be REFLECT, CONSTANT,
+            tf.pad() / np.pad() padding mode. Can be REFLECT, CONSTANT,
             or SYMMETRIC
+        option : str
+            Option for TensorFlow padding ("tf") or numpy ("np"). Default is tf
+            for tensorflow training. We have observed silent failures of
+            tf.pad() with larger array sizes, so "np" might be preferable at
+            inference time on large chunks, but it is much slower when it has
+            to convert tensors to numpy arrays.
         """
         super().__init__()
         self.paddings = tf.constant(paddings)
         self.rank = len(paddings)
-        self.mode = mode
+        self.mode = mode.lower()
+        self.option = option.lower()
+
+        if self.option == 'tf':
+            self._pad_fun = tf.pad
+        elif self.option == 'np':
+            self._pad_fun = np.pad
+        else:
+            msg = ('FlexiblePadding option must be "tf" or "np" but '
+                   f'received: {self.option}')
+            logger.error(msg)
+            raise KeyError(msg)
 
     def compute_output_shape(self, input_shape):
         """Computes output shape after padding
@@ -62,8 +79,7 @@ def call(self, x):
             by compute_output_shape
 
         """
-        return tf.pad(x, self.paddings,
-                      mode=self.mode)
+        return self._pad_fun(x, self.paddings, mode=self.mode)
 
 
 class ExpandDims(tf.keras.layers.Layer):
@@ -168,6 +184,7 @@ def __init__(self, pool_size, strides=None, padding='valid', sigma=1,
         self.trainable = trainable
         self.sigma = sigma
 
+    # pylint: disable=unused-argument
     def build(self, input_shape):
         """Custom implementation of the tf layer build method.
 
@@ -475,11 +492,13 @@ def __init__(self, spatial_mult=1, temporal_mult=1,
             where the feature axis is unpacked into the temporal axis.
         t_roll : int
             Option to roll the temporal axis after expanding. When using
-            temporal_method="depth_to_time", the default (t_roll=0) will
-            add temporal steps after the input steps such that if input
-            temporal shape is 3 and the temporal_mult is 24x, the output will
-            have the original timesteps at idt=0,24,48 but if t_roll=12, the
-            output will have the original timesteps at idt=12,36,60
+            temporal_method="depth_to_time", the default (t_roll=0) will add
+            temporal steps after the input steps such that if input temporal
+            shape is 3 and the temporal_mult is 24x, the output will have the
+            index-0 timesteps at idt=0,24,48 but if t_roll=12, the output will
+            have the original timesteps at idt=12,36,60. This is no longer
+            recommended, as a positive roll will move the features of timestep
+            -1 from the end of the series to the beginning.
         """
 
         super().__init__()
diff --git a/phygnn/version.py b/phygnn/version.py
index 7e5a600..cbd42b5 100644
--- a/phygnn/version.py
+++ b/phygnn/version.py
@@ -1,4 +1,4 @@
 # -*- coding: utf-8 -*-
 """Physics Guided Neural Network version."""
 
-__version__ = '0.0.29'
+__version__ = '0.0.30'
diff --git a/tests/test_layers.py b/tests/test_layers.py
index 3a117e0..10758de 100644
--- a/tests/test_layers.py
+++ b/tests/test_layers.py
@@ -289,17 +289,17 @@ def test_flexible_padding(hidden_layers):
     layer = HiddenLayers(hidden_layers).layers[0]
     t = tf.constant([[1, 2, 3],
                      [4, 5, 6]])
-    if layer.mode == 'CONSTANT':
+    if layer.mode.upper() == 'CONSTANT':
         t_check = tf.constant([[0, 0, 0, 0, 0, 0, 0],
                                [0, 0, 1, 2, 3, 0, 0],
                                [0, 0, 4, 5, 6, 0, 0],
                                [0, 0, 0, 0, 0, 0, 0]])
-    elif layer.mode == 'REFLECT':
+    elif layer.mode.upper() == 'REFLECT':
         t_check = tf.constant([[6, 5, 4, 5, 6, 5, 4],
                                [3, 2, 1, 2, 3, 2, 1],
                                [6, 5, 4, 5, 6, 5, 4],
                                [3, 2, 1, 2, 3, 2, 1]])
-    elif layer.mode == 'SYMMETRIC':
+    elif layer.mode.upper() == 'SYMMETRIC':
         t_check = tf.constant([[2, 1, 1, 2, 3, 3, 2],
                                [2, 1, 1, 2, 3, 3, 2],
                                [5, 4, 4, 5, 6, 6, 5],