diff --git a/custom_components/localthings/registry/capabilities/common.py b/custom_components/localthings/registry/capabilities/common.py
index ac60523..4ed9bab 100644
--- a/custom_components/localthings/registry/capabilities/common.py
+++ b/custom_components/localthings/registry/capabilities/common.py
@@ -91,12 +91,25 @@ def _ml_to_l(v):
 
 
 def _active_alarm_codes(items):
-    """Join active alarm codes; skip retained rows Samsung leaves as Deleted.
+    """Join active alarm codes; skip retained rows Samsung leaves as Deleted,
+    and any code ending in '_OFF'.
 
     Laundry boards keep a Deleted ErrorCode row in /alarms/vs/0 after the
     condition clears (see WD7000B diagnostics). Surface only live alarms so
-    HA doesn't stick on a stale ErrorCode. Range-hood has its own stricter
-    helper that also drops ErrorCode_OFF.
+    HA doesn't stick on a stale ErrorCode.
+
+    Samsung pre-populates this array with one row per alarm *type* the board
+    supports, each carrying its own '<Name>_OFF' placeholder code when that
+    alarm isn't firing -- confirmed across independent device families
+    (ErrorCode_OFF, FilterAlarm_OFF, OV_E_OFF, CT_E_OFF, WaterTankFull_OFF,
+    AC_V_0002_OFF all appear in fixtures with no corresponding active
+    condition). An alarm that's actually firing instead reports a plain,
+    unsuffixed code (FilterAlarm, DoorA_Opened, SNSF_Reached) -- issue #166's
+    AC dump has both a FilterAlarm_OFF placeholder and shows what a live
+    filter alert looks like: code 'FilterAlarm' (no suffix), state
+    'Created'. Range-hood previously special-cased only the literal
+    'ErrorCode_OFF' string in its own stricter helper; this generalizes
+    the same rule to the whole '_OFF' suffix convention.
     """
     if not items or not isinstance(items, list):
         return 'none'
@@ -105,6 +118,7 @@ def _active_alarm_codes(items):
         for i in items
         if i.get('x.com.samsung.da.code')
         and str(i.get('x.com.samsung.da.state', '')).lower() != 'deleted'
+        and not str(i.get('x.com.samsung.da.code', '')).lower().endswith('_off')
     ]
     return ', '.join(codes) if codes else 'none'
 
diff --git a/tests/test_common_capabilities.py b/tests/test_common_capabilities.py
index 2050a70..d536165 100644
--- a/tests/test_common_capabilities.py
+++ b/tests/test_common_capabilities.py
@@ -184,6 +184,40 @@ class TestWmSetinfoFlags:
             },
         ]) == 'LE'
 
+    def test_off_suffixed_placeholder_codes_filtered(self):
+        """issue #166: Samsung pre-populates /alarms/vs/0 with one row per
+        supported alarm *type*, each carrying a '<Name>_OFF' placeholder
+        code (no 'Deleted' state at all) when that alarm isn't firing --
+        confirmed not just for 'ErrorCode_OFF' but also 'FilterAlarm_OFF'
+        on the same dump. These were previously shown as if they were
+        active alarms."""
+        assert common._active_alarm_codes([
+            {
+                'x.com.samsung.da.code': 'ErrorCode_OFF',
+                'x.com.samsung.da.triggeredTime': '2026-07-28T12:59:22',
+            },
+            {
+                'x.com.samsung.da.code': 'FilterAlarm_OFF',
+                'x.com.samsung.da.triggeredTime': '2026-07-28T12:59:22',
+            },
+        ]) == 'none'
+
+    def test_real_filter_alarm_not_off_suffixed_still_shown(self):
+        """issue #166's actual live filter alert: code 'FilterAlarm' (no
+        '_OFF' suffix), state 'Created' -- distinct from the 'FilterAlarm_OFF'
+        placeholder and must still surface."""
+        assert common._active_alarm_codes([
+            {
+                'x.com.samsung.da.code': 'ErrorCode_OFF',
+                'x.com.samsung.da.triggeredTime': '2026-07-28T12:59:22',
+            },
+            {
+                'x.com.samsung.da.code': 'FilterAlarm',
+                'x.com.samsung.da.state': 'Created',
+                'x.com.samsung.da.triggeredTime': '2026-07-28T12:59:22',
+            },
+        ]) == 'FilterAlarm'
+
 
 class TestKidsLockFallback:
     def test_generic_read_write(self):