diff --git a/salt/elasticsearch/soc_elasticsearch.yaml b/salt/elasticsearch/soc_elasticsearch.yaml
index 27d5654b5..7fd4f8329 100644
--- a/salt/elasticsearch/soc_elasticsearch.yaml
+++ b/salt/elasticsearch/soc_elasticsearch.yaml
@@ -149,7 +149,7 @@ elasticsearch:
                 max_primary_shard_size:
                   title: max shard size
                   description: Desired shard size in gb/tb/pb eg. 100gb. Note that this value is only used when the shrink method selected is 'SIZE'.
-                  regex: ^(?:[0-9]+(?:gb|tb|pb)|)$
+                  regex: ^[0-9]+(?:gb|tb|pb)$
                   global: True
                   forcedType: string
                   advanced: True
@@ -222,7 +222,7 @@ elasticsearch:
                 max_primary_shard_size:
                   title: max shard size
                   description: Desired shard size in gb/tb/pb eg. 100gb. Note that this value is only used when the shrink method selected is 'SIZE'.
-                  regex: ^(?:[0-9]+(?:gb|tb|pb)|)$
+                  regex: ^[0-9]+(?:gb|tb|pb)$
                   global: True
                   forcedType: string
                   advanced: True
@@ -398,7 +398,7 @@ elasticsearch:
                 max_primary_shard_size:
                   title: max shard size
                   description: Desired shard size in gb/tb/pb eg. 100gb. Note that this value is only used when the shrink method selected is 'SIZE'.
-                  regex: ^(?:[0-9]+(?:gb|tb|pb)|)$
+                  regex: ^[0-9]+(?:gb|tb|pb)$
                   global: True
                   forcedType: string
                   advanced: True
@@ -465,7 +465,7 @@ elasticsearch:
                 max_primary_shard_size:
                   title: max shard size
                   description: Desired shard size in gb/tb/pb eg. 100gb. Note that this value is only used when the shrink method selected is 'SIZE'.
-                  regex: ^(?:[0-9]+(?:gb|tb|pb)|)$
+                  regex: ^[0-9]+(?:gb|tb|pb)$
                   global: True
                   forcedType: string
                   advanced: True