diff --git a/core/import-csv.c b/core/import-csv.c
index a815408a8..dda4b8b79 100644
--- a/core/import-csv.c
+++ b/core/import-csv.c
@@ -554,6 +554,8 @@ int parse_txt_file(const char *filename, const char *csv, struct dive_table *tab
 		cyl.type.description = "3l Mk6";
 		cyl.gasmix.o2.permille = 1000;
 		cyl.manually_added = true;
+		cyl.bestmix_o2 = 0;
+		cyl.bestmix_he = 0;
 		add_cloned_cylinder(&dive->cylinders, cyl);
 
 		cyl.cylinder_use = DILUENT;