diff --git a/src/sp2xr/helpers.py b/src/sp2xr/helpers.py
index f80e7be..0d0cad6 100644
--- a/src/sp2xr/helpers.py
+++ b/src/sp2xr/helpers.py
@@ -218,7 +218,7 @@ def parse_args():
         "--hist", action="store_true", help="write size/mass/time-lag histograms"
     )
     p.add_argument(
-        "--dt", type=int, default=1, help="aggregation interval in seconds (default: 1)"
+        "--dt", type=int, default=None, help="aggregation interval in seconds"
     )
 
     # BC proeprties
@@ -232,16 +232,10 @@ def parse_args():
 
     # cluster / resource knobs (all optional)
     p.add_argument("--local", action="store_false", help="Run Local Cluster")
-    p.add_argument(
-        "--cores", type=int, default=8, help="CPU cores per SLURM job (default: 8)"
-    )
-    p.add_argument("--memory", default="64GB", help="RAM per job (default: 64GB)")
-    p.add_argument(
-        "--walltime", default="00:59:00", help="SLURM wall-time (default: 1h)"
-    )
-    p.add_argument(
-        "--partition", default="hourly", help="SLURM partition (default: hourly)"
-    )
+    p.add_argument("--cores", type=int, default=None, help="CPU cores per SLURM job")
+    p.add_argument("--memory", default=None, help="RAM per job")
+    p.add_argument("--walltime", default=None, help="SLURM wall-time")
+    p.add_argument("--partition", default=None, help="SLURM partition")
     p.add_argument("--set", action="append", default=[], help="dot.notation overrides")
     return p.parse_args()