diff --git a/src/Control/Concurrent/BloomFilter/Internal.hs b/src/Control/Concurrent/BloomFilter/Internal.hs
--- a/src/Control/Concurrent/BloomFilter/Internal.hs
+++ b/src/Control/Concurrent/BloomFilter/Internal.hs
@@ -214,7 +214,7 @@
     unless (dataSzBytes >= sIZEOF_INT) $ Left "Array is not large enough to be a serialized bloom filter"
     unless (isPowerOfTwo dataSzWds && z == 0) $ Left "Array is an unexpected size for a serialized bloom filter"
     return $!
-      countTrailingZeros dataSzWds -- logBase 2, when isPowerOfTwo
+      popCount (dataSzWds - 1) -- logBase 2, when isPowerOfTwo dataSzWds
   
 
 
diff --git a/unagi-bloomfilter.cabal b/unagi-bloomfilter.cabal
--- a/unagi-bloomfilter.cabal
+++ b/unagi-bloomfilter.cabal
@@ -1,5 +1,5 @@
 name:                unagi-bloomfilter
-version:             0.1.1.1
+version:             0.1.1.2
 synopsis:            A fast, cache-efficient, concurrent bloom filter
 description:
   This library implements a fast concurrent bloom filter, based on bloom-1 from