diff --git a/tools/check_reward_v1.py b/tools/check_reward_v1.py
index 348ab0c..e93d38c 100644
--- a/tools/check_reward_v1.py
+++ b/tools/check_reward_v1.py
@@ -84,7 +84,7 @@ def get_session_validator(substrate):
             module='ParachainStaking',
             storage_function='CandidatePool',
             params=[block_author],
-            block_hash=block_hash,
+            block_hash=previous_block_hash,
         )
         staking_info[block_author] = info.value
         staking_info[block_author]['delegators'] = {