diff --git a/app/services/firebird_service.py b/app/services/firebird_service.py
index aeedc1c..79578b9 100644
--- a/app/services/firebird_service.py
+++ b/app/services/firebird_service.py
@@ -9,16 +9,20 @@ def _safe(v):
     if v is None:
         return None
     if isinstance(v, datetime.datetime):
-        return v.isoformat()
+        return v.strftime("%Y-%m-%dT%H:%M:%S")
     if isinstance(v, datetime.date):
         return v.isoformat()
+    if isinstance(v, datetime.time):
+        return v.strftime("%H:%M:%S")
     if isinstance(v, decimal.Decimal):
         return float(v)
     if isinstance(v, (bytes, bytearray, memoryview)):
         return f"<BLOB {len(v)} bytes>"
-    if isinstance(v, (int, float, str, bool)):
+    if isinstance(v, (int, float, bool)):
         return v
-    return str(v)
+    # strings: strip any spaces around colons (Firebird sometimes returns "12: 47: 37")
+    s = str(v)
+    return re.sub(r'\s*:\s*', ':', s) if ':' in s else s
 
 
 class FirebirdService: