diff --git a/workflows/prefactor_calibrator/ion.cwl b/workflows/prefactor_calibrator/ion.cwl
index 4efead5554e7ed07ec87e4c5086206d9b7dd2077..94f73066cf133126a2ec61f50786d632cec47769 100644
--- a/workflows/prefactor_calibrator/ion.cwl
+++ b/workflows/prefactor_calibrator/ion.cwl
@@ -237,8 +237,6 @@ steps:
           - freq
       - id: axisInTable
         default: ant
-      - id: axisDiff
-        default: pol
       - id: minmax
         default:
           - -3.14