diff --git a/cscs-checks/system/slurm/slurm.py b/cscs-checks/system/slurm/slurm.py
index 347b6105ed..c19b4dc030 100644
--- a/cscs-checks/system/slurm/slurm.py
+++ b/cscs-checks/system/slurm/slurm.py
@@ -112,7 +112,7 @@ def __init__(self):
 
     @rfm.run_before('run')
     def set_memory_limit(self):
-        self.job.options += ['--mem=120000']
+        self.job.options = ['--mem=120000']
 
 
 @rfm.simple_test
@@ -171,7 +171,7 @@ def __init__(self):
     def set_slurm_constraint(self):
         cabinet = self.cabinets.get(self.current_partition.fullname)
         if cabinet:
-            self.job.options += [f'--constraint={cabinet}']
+            self.job.options = [f'--constraint={cabinet}']
 
 
 @rfm.simple_test
@@ -188,7 +188,7 @@ def __init__(self):
 
     @rfm.run_before('run')
     def set_memory_limit(self):
-        self.job.options += ['--mem=2000']
+        self.job.options = ['--mem=2000']
 
 
 @rfm.simple_test