diff --git a/zstd_h5plugin.c b/zstd_h5plugin.c
index 5a3dfd3..a527f1f 100644
--- a/zstd_h5plugin.c
+++ b/zstd_h5plugin.c
@@ -35,8 +35,8 @@ DLL_EXPORT size_t zstd_filter(unsigned int flags, size_t cd_nelmts,
 			aggression = (int)cd_values[0];
 		else
 			aggression = ZSTD_CLEVEL_DEFAULT;
-		if (aggression < 1 /*ZSTD_minCLevel()*/)
-			aggression = 1 /*ZSTD_minCLevel()*/;
+		if (aggression < ZSTD_minCLevel())
+			aggression = ZSTD_minCLevel();
 		else if (aggression > ZSTD_maxCLevel())
 			aggression = ZSTD_maxCLevel();