diff --git a/term_frag_sel/cli.py b/term_frag_sel/cli.py
index 30c2535c219bf40e94ef441f075d99f5ab628884..93fafbb197c9a582e0281f33e443163bb0fca26e 100644
--- a/term_frag_sel/cli.py
+++ b/term_frag_sel/cli.py
@@ -135,7 +135,6 @@ def parse_arguments() -> argparse.Namespace:
                         type=check_positive,
                         help="Chunk size for batch processing")
     parser.add_argument('--sep', required=False, default=",",
-                        type=check_positive,
                         help="Sequence counts file separator.")
     args = parser.parse_args()