diff --git a/libconfluo/confluo/container/sketch/confluo_universal_sketch.h b/libconfluo/confluo/container/sketch/confluo_universal_sketch.h
index ac9a4ea61..ab16a4130 100644
--- a/libconfluo/confluo/container/sketch/confluo_universal_sketch.h
+++ b/libconfluo/confluo/container/sketch/confluo_universal_sketch.h
@@ -364,7 +364,7 @@ class confluo_universal_sketch {
   }
 
   std::vector<confluo_substream_summary<counter_t>> substream_summaries_;
-  hash_manager<size_t> layer_hashes_;
+  hash_manager layer_hashes_;
 
   schema_t schema_;
   column_t column_;
diff --git a/libconfluo/confluo/container/sketch/count_sketch.h b/libconfluo/confluo/container/sketch/count_sketch.h
index f3be7b3ad..c69fe1196 100644
--- a/libconfluo/confluo/container/sketch/count_sketch.h
+++ b/libconfluo/confluo/container/sketch/count_sketch.h
@@ -167,8 +167,8 @@ class count_sketch {
   size_t width_; // number of buckets
 
   std::vector<atomic_counter_t> counters_;
-  hash_manager<T> bucket_hash_manager_;
-  hash_manager<T> sign_hash_manager_;
+  hash_manager bucket_hash_manager_;
+  hash_manager sign_hash_manager_;
 
 };
 
diff --git a/libconfluo/confluo/container/sketch/hash_manager.h b/libconfluo/confluo/container/sketch/hash_manager.h
index 04fa98aad..f7ed9122f 100644
--- a/libconfluo/confluo/container/sketch/hash_manager.h
+++ b/libconfluo/confluo/container/sketch/hash_manager.h
@@ -13,16 +13,11 @@ namespace sketch {
 class pairwise_indep_hash {
 
  public:
-  static const size_t PRIME = 39916801UL;
+  static const size_t PRIME;
 
-  pairwise_indep_hash()
-      : pairwise_indep_hash(0, 0) {
-  }
+  pairwise_indep_hash();
 
-  pairwise_indep_hash(size_t a, size_t b)
-      : a_(a),
-        b_(b) {
-  }
+  pairwise_indep_hash(size_t a, size_t b);
 
   template<typename T>
   size_t apply(T elem) const {
@@ -35,40 +30,27 @@ class pairwise_indep_hash {
     return (a_ * elem + b_) % PRIME;
   }
 
-  static pairwise_indep_hash generate_random() {
-    return { utils::rand_utils::rand_uint64(PRIME), utils::rand_utils::rand_uint64(PRIME) };
-  }
+  static pairwise_indep_hash generate_random();
 
  private:
   size_t a_, b_;
 
 };
 
-const size_t pairwise_indep_hash::PRIME;
-
-template<typename T>
 class hash_manager {
  public:
+
   /**
    * Constructor.
    * @param num_hashes number of hashes
    */
-  hash_manager(size_t num_hashes = 0)
-      : hashes_() {
-    this->guarantee_initialized(num_hashes);
-  }
+  explicit hash_manager(size_t num_hashes = 0);
 
   /**
    * Guarantee enough hashes are intialized.
    * @param num_hashes number of hashes
    */
-  void guarantee_initialized(size_t num_hashes) {
-    size_t cur_size = hashes_.size();
-    size_t num_new_hashes = num_hashes > cur_size ? num_hashes - cur_size : 0;
-    for (size_t i = 0; i < num_new_hashes; i++) {
-      hashes_.push_back(pairwise_indep_hash::generate_random());
-    }
-  }
+  void guarantee_initialized(size_t num_hashes);
 
   /**
    * Hash element.
@@ -76,6 +58,7 @@ class hash_manager {
    * @param elem element to hash
    * @return hashed value
    */
+  template<typename T>
   size_t hash(size_t hash_id, T elem) const {
     return hashes_[hash_id].template apply<T>(elem);
   }
diff --git a/libconfluo/confluo/container/sketch/universal_sketch.h b/libconfluo/confluo/container/sketch/universal_sketch.h
index 5924640be..2992a77f1 100644
--- a/libconfluo/confluo/container/sketch/universal_sketch.h
+++ b/libconfluo/confluo/container/sketch/universal_sketch.h
@@ -363,7 +363,7 @@ class universal_sketch {
   }
 
   std::vector<substream_summary<T, counter_t>> substream_summaries_;
-  hash_manager<T> layer_hashes_;
+  hash_manager layer_hashes_;
 
   bool precise_hh_;
 
diff --git a/libconfluo/src/container/sketch/hash_manager.cc b/libconfluo/src/container/sketch/hash_manager.cc
new file mode 100644
index 000000000..059bbb4b9
--- /dev/null
+++ b/libconfluo/src/container/sketch/hash_manager.cc
@@ -0,0 +1,36 @@
+#include "container/sketch/hash_manager.h"
+
+namespace confluo {
+namespace sketch {
+
+const size_t pairwise_indep_hash::PRIME = 39916801UL;
+
+pairwise_indep_hash::pairwise_indep_hash()
+    : pairwise_indep_hash(0, 0) {
+}
+
+pairwise_indep_hash::pairwise_indep_hash(size_t a, size_t b)
+        : a_(a),
+          b_(b) {
+}
+
+
+pairwise_indep_hash pairwise_indep_hash::generate_random() {
+  return { utils::rand_utils::rand_uint64(PRIME), utils::rand_utils::rand_uint64(PRIME) };
+}
+
+hash_manager::hash_manager(size_t num_hashes)
+        : hashes_() {
+  this->guarantee_initialized(num_hashes);
+}
+
+void hash_manager::guarantee_initialized(size_t num_hashes) {
+  size_t cur_size = hashes_.size();
+  size_t num_new_hashes = num_hashes > cur_size ? num_hashes - cur_size : 0;
+  for (size_t i = 0; i < num_new_hashes; i++) {
+    hashes_.push_back(pairwise_indep_hash::generate_random());
+  }
+}
+
+}
+}