diff --git a/config/config.go b/config/config.go
index cd162a55..ad468df0 100644
--- a/config/config.go
+++ b/config/config.go
@@ -91,5 +91,6 @@ import (
 	_ "github.com/blevesearch/bleve/index/store/moss"
 
 	// index types
+	_ "github.com/blevesearch/bleve/index/smolder"
 	_ "github.com/blevesearch/bleve/index/upside_down"
 )
diff --git a/index/smolder/smoldering.go b/index/smolder/smoldering.go
index 0465c815..4ec311dd 100644
--- a/index/smolder/smoldering.go
+++ b/index/smolder/smoldering.go
@@ -387,7 +387,7 @@ func (udc *SmolderingCouch) countDocs(kvreader store.KVReader) (count, highDocNu
 	}
 
 	if lastValidK != nil {
-		_, highDocNum, err = DecodeUvarintAscending(k[1:])
+		_, highDocNum, err = DecodeUvarintAscending(lastValidK[1:])
 		if err != nil {
 			return 0, 0, err
 		}