diff --git a/src/pineko/theory.py b/src/pineko/theory.py
index cbb4ea31..5242aa50 100644
--- a/src/pineko/theory.py
+++ b/src/pineko/theory.py
@@ -320,7 +320,7 @@ def eko(self, name, _grid, tcard):
         logger.info("Start computation of %s", name)
         start_time = time.perf_counter()
         ops = eko.run_dglap(theory_card=tcard, operators_card=ocard)
-        ops.deepcopy(eko_filename)
+        ops.dump_tar(eko_filename)
         logger.info(
             "Finished computation of %s - took %f s",
             name,