diff --git a/kikuchipy/indexing/_hough_indexing.py b/kikuchipy/indexing/_hough_indexing.py
index 87cd7353..1e68c02c 100644
--- a/kikuchipy/indexing/_hough_indexing.py
+++ b/kikuchipy/indexing/_hough_indexing.py
@@ -452,10 +452,11 @@ def _phase_lists_are_compatible(
     if n_phases != n_phases_pei:
         compatible = False
         msg = (
-            f"`phase_list` and `indexer.phaselist` have unequal lengths {n_phases} and "
-            f"{n_phases_pei}"
+            f"`phase_list` ({n_phases}) and `indexer.phaselist` ({n_phases_pei}) have "
+            "unequal number of phases"
         )
     else:
+        i = 0
         for (_, phase), phase_pei in zip(phase_list, phase_list_pei):
             lat = phase.structure.lattice.abcABG()
             lat_pei = phase_pei.latticeparameter
@@ -465,7 +466,7 @@ def _phase_lists_are_compatible(
             if not np.allclose(lat, lat_pei, atol=1e-12):
                 compatible = False
                 msg = (
-                    f"Phase '{phase.name}' in `phase_list` and {phase_pei} in "
+                    f"Phase '{phase.name}' in `phase_list` and phase number {i} in "
                     f"`indexer.phaselist` have unequal lattice parameters {lat} and "
                     f"{lat_pei}"
                 )
@@ -473,12 +474,14 @@ def _phase_lists_are_compatible(
             elif sg != sg_pei:
                 compatible = False
                 msg = (
-                    f"Phase '{phase.name}' in `phase_list` and {phase_pei} in "
+                    f"Phase '{phase.name}' in `phase_list` and phase number {i} in "
                     f"`indexer.phaselist` have unequal space group numbers {sg} and "
                     f"{sg_pei}"
                 )
                 break
 
+            i += 1
+
     if raise_if_not and not compatible:
         raise ValueError(msg)
     else:
diff --git a/kikuchipy/signals/tests/test_ebsd_hough_indexing.py b/kikuchipy/signals/tests/test_ebsd_hough_indexing.py
index 9008cd1d..67fb66d6 100644
--- a/kikuchipy/signals/tests/test_ebsd_hough_indexing.py
+++ b/kikuchipy/signals/tests/test_ebsd_hough_indexing.py
@@ -18,7 +18,7 @@
 from diffpy.structure import Lattice, Structure
 from diffsims.crystallography import ReciprocalLatticeVector
 import numpy as np
-from orix.crystal_map import CrystalMap, PhaseList
+from orix.crystal_map import CrystalMap, Phase, PhaseList
 import pytest
 
 import kikuchipy as kp
@@ -135,7 +135,9 @@ def test_hough_indexing_return_band_data(self):
 
     def test_hough_indexing_raises_dissimilar_phase_lists(self):
         phase_list = PhaseList(names=["a", "b"], space_groups=[225, 229])
-        with pytest.raises(ValueError, match=r"`phase_list` and `indexer.phaselist` "):
+        with pytest.raises(
+            ValueError, match=r"`phase_list` \(2\) and `indexer.phaselist` \(1\) have "
+        ):
             _ = self.signal.hough_indexing(phase_list, self.indexer)
 
     def test_indexer_is_compatible_with_signal(self):
@@ -227,6 +229,21 @@ def test_reflector_list(self):
 
             assert np.allclose(indexer.phaselist[0].polefamilies, hkl)
 
+    def test_reflector_lists(self):
+        phase_list = PhaseList(names=["a", "b"], space_groups=[186, 225])
+        hkl = [
+            [[0, 0, 6], [0, 0, -6], [1, 0, 0], [2, 0, 0]],
+            [[2, 0, 0], [2, 2, 0]],
+            [[1, 1, 1], [3, 1, 1], [3, 3, 1]],
+        ]
+
+        _ = self.signal.detector.get_indexer(phase_list, hkl[:2])
+        _ = self.signal.detector.get_indexer(phase_list, [hkl[0], None])
+        _ = self.signal.detector.get_indexer(phase_list, [None, None])
+
+        with pytest.raises(ValueError, match="One set of reflectors or None must be "):
+            _ = self.signal.detector.get_indexer(phase_list, hkl)
+
     def test_compatible_phase_lists(self):
         phase_list = PhaseList(
             names=["a", "b"],
@@ -240,6 +257,32 @@ def test_compatible_phase_lists(self):
 
         assert _phase_lists_are_compatible(phase_list, indexer, True)
 
+        # Differing number of phases
+        phase_list2 = phase_list.deepcopy()
+        phase_list2.add(Phase("c", space_group=1))
+        assert not _phase_lists_are_compatible(phase_list2, indexer)
+        with pytest.raises(
+            ValueError, match=r"`phase_list` \(3\) and `indexer.phaselist` \(2\)"
+        ):
+            _ = _phase_lists_are_compatible(phase_list2, indexer, True)
+
+        # Differing lattice parameters
+        phase_list3 = phase_list.deepcopy()
+        lat = phase_list3["a"].structure.lattice
+        lat.setLatPar(lat.a * 10)
+        with pytest.raises(
+            ValueError, match="Phase 'a' in `phase_list` and phase number 0 in "
+        ):
+            _ = _phase_lists_are_compatible(phase_list3, indexer, True)
+
+        # Differing space groups
+        phase_list4 = phase_list.deepcopy()
+        phase_list4["b"].space_group = 224
+        with pytest.raises(
+            ValueError, match="Phase 'b' in `phase_list` and phase number 1 in "
+        ):
+            _ = _phase_lists_are_compatible(phase_list4, indexer, True)
+
 
 @pytest.mark.skipif(
     not kp._pyebsdindex_installed, reason="pyebsdindex is not installed"