diff --git a/implementations/onblocks/BlobStoreOnBlocks.cpp b/implementations/onblocks/BlobStoreOnBlocks.cpp
index 5ba84194..68780823 100644
--- a/implementations/onblocks/BlobStoreOnBlocks.cpp
+++ b/implementations/onblocks/BlobStoreOnBlocks.cpp
@@ -12,10 +12,15 @@
 using std::unique_ptr;
 using std::make_unique;
 
+using cpputils::unique_ref;
+using cpputils::make_unique_ref;
+
 using blockstore::BlockStore;
 using blockstore::parallelaccess::ParallelAccessBlockStore;
 using blockstore::Key;
 using cpputils::dynamic_pointer_move;
+using boost::optional;
+using boost::none;
 
 namespace blobstore {
 namespace onblocks {
@@ -31,19 +36,19 @@ BlobStoreOnBlocks::BlobStoreOnBlocks(unique_ptr<BlockStore> blockStore, uint32_t
 BlobStoreOnBlocks::~BlobStoreOnBlocks() {
 }
 
-unique_ptr<Blob> BlobStoreOnBlocks::create() {
-  return make_unique<BlobOnBlocks>(_dataTreeStore->createNewTree());
+unique_ref<Blob> BlobStoreOnBlocks::create() {
+  return make_unique_ref<BlobOnBlocks>(_dataTreeStore->createNewTree());
 }
 
-unique_ptr<Blob> BlobStoreOnBlocks::load(const Key &key) {
+optional<unique_ref<Blob>> BlobStoreOnBlocks::load(const Key &key) {
   auto tree = _dataTreeStore->load(key);
   if (tree == nullptr) {
-  	return nullptr;
+  	return none;
   }
-  return make_unique<BlobOnBlocks>(std::move(tree));
+  return optional<unique_ref<Blob>>(make_unique_ref<BlobOnBlocks>(std::move(tree)));
 }
 
-void BlobStoreOnBlocks::remove(unique_ptr<Blob> blob) {
+void BlobStoreOnBlocks::remove(unique_ref<Blob> blob) {
   auto _blob = dynamic_pointer_move<BlobOnBlocks>(blob);
   _dataTreeStore->remove(_blob->releaseTree());
 }
diff --git a/implementations/onblocks/BlobStoreOnBlocks.h b/implementations/onblocks/BlobStoreOnBlocks.h
index 0a2cd2ea..a01922f5 100644
--- a/implementations/onblocks/BlobStoreOnBlocks.h
+++ b/implementations/onblocks/BlobStoreOnBlocks.h
@@ -18,10 +18,10 @@ public:
   BlobStoreOnBlocks(std::unique_ptr<blockstore::BlockStore> blockStore, uint32_t blocksizeBytes);
   virtual ~BlobStoreOnBlocks();
 
-  std::unique_ptr<Blob> create() override;
-  std::unique_ptr<Blob> load(const blockstore::Key &key) override;
+  cpputils::unique_ref<Blob> create() override;
+  boost::optional<cpputils::unique_ref<Blob>> load(const blockstore::Key &key) override;
 
-  void remove(std::unique_ptr<Blob> blob) override;
+  void remove(cpputils::unique_ref<Blob> blob) override;
 
 private:
   std::unique_ptr<parallelaccessdatatreestore::ParallelAccessDataTreeStore> _dataTreeStore;
diff --git a/interface/BlobStore.h b/interface/BlobStore.h
index 4941f137..d9871495 100644
--- a/interface/BlobStore.h
+++ b/interface/BlobStore.h
@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "messmer/blockstore/utils/Key.h"
+#include <messmer/cpp-utils/unique_ref.h>
 
 namespace blobstore {
 
@@ -14,11 +15,9 @@ class BlobStore {
 public:
   virtual ~BlobStore() {}
 
-  virtual std::unique_ptr<Blob> create() = 0;
-  //TODO Use boost::optional (if key doesn't exist)
-  // Return nullptr if block with this key doesn't exists
-  virtual std::unique_ptr<Blob> load(const blockstore::Key &key) = 0;
-  virtual void remove(std::unique_ptr<Blob> blob) = 0;
+  virtual cpputils::unique_ref<Blob> create() = 0;
+  virtual boost::optional<cpputils::unique_ref<Blob>> load(const blockstore::Key &key) = 0;
+  virtual void remove(cpputils::unique_ref<Blob> blob) = 0;
 };
 
 }
diff --git a/test/implementations/onblocks/BlobReadWriteTest.cpp b/test/implementations/onblocks/BlobReadWriteTest.cpp
index 0ff562a8..9f63a479 100644
--- a/test/implementations/onblocks/BlobReadWriteTest.cpp
+++ b/test/implementations/onblocks/BlobReadWriteTest.cpp
@@ -3,7 +3,7 @@
 #include <messmer/cpp-utils/data/DataFixture.h>
 #include "../../../implementations/onblocks/datanodestore/DataNodeView.h"
 
-using std::unique_ptr;
+using cpputils::unique_ref;
 using ::testing::WithParamInterface;
 using ::testing::Values;
 
@@ -37,7 +37,7 @@ public:
   }
 
   Data randomData;
-  unique_ptr<Blob> blob;
+  unique_ref<Blob> blob;
 };
 constexpr uint32_t BlobReadWriteTest::LARGE_SIZE;
 constexpr DataNodeLayout BlobReadWriteTest::LAYOUT;
@@ -45,14 +45,14 @@ constexpr DataNodeLayout BlobReadWriteTest::LAYOUT;
 TEST_F(BlobReadWriteTest, WritingImmediatelyFlushes_SmallSize) {
 	blob->resize(5);
 	blob->write(randomData.data(), 0, 5);
-	auto loaded = blobStore->load(blob->key());
+	auto loaded = loadBlob(blob->key());
 	EXPECT_DATA_READS_AS(randomData, *loaded, 0, 5);
 }
 
 TEST_F(BlobReadWriteTest, WritingImmediatelyFlushes_LargeSize) {
 	blob->resize(LARGE_SIZE);
 	blob->write(randomData.data(), 0, LARGE_SIZE);
-	auto loaded = blobStore->load(blob->key());
+	auto loaded = loadBlob(blob->key());
 	EXPECT_DATA_READS_AS(randomData, *loaded, 0, LARGE_SIZE);
 }
 
@@ -127,7 +127,7 @@ TEST_P(BlobReadWriteDataTest, WriteAndReadImmediately) {
 TEST_P(BlobReadWriteDataTest, WriteAndReadAfterLoading) {
   blob->resize(GetParam().blobsize);
   blob->write(this->foregroundData.data(), GetParam().offset, GetParam().count);
-  auto loaded = blobStore->load(blob->key());
+  auto loaded = loadBlob(blob->key());
 
   EXPECT_DATA_READS_AS(this->foregroundData, *loaded, GetParam().offset, GetParam().count);
   EXPECT_DATA_IS_ZEROES_OUTSIDE_OF(*loaded, GetParam().offset, GetParam().count);
diff --git a/test/implementations/onblocks/BlobSizeTest.cpp b/test/implementations/onblocks/BlobSizeTest.cpp
index 16e5077c..a972f551 100644
--- a/test/implementations/onblocks/BlobSizeTest.cpp
+++ b/test/implementations/onblocks/BlobSizeTest.cpp
@@ -2,12 +2,11 @@
 #include <messmer/cpp-utils/data/Data.h>
 #include <messmer/cpp-utils/data/DataFixture.h>
 
-using std::unique_ptr;
-
 using namespace blobstore;
 using blockstore::Key;
 using cpputils::Data;
 using cpputils::DataFixture;
+using cpputils::unique_ref;
 
 class BlobSizeTest: public BlobStoreTest {
 public:
@@ -16,7 +15,7 @@ public:
   static constexpr uint32_t MEDIUM_SIZE = 5 * 1024 * 1024;
   static constexpr uint32_t LARGE_SIZE = 10 * 1024 * 1024;
 
-  unique_ptr<Blob> blob;
+  unique_ref<Blob> blob;
 };
 constexpr uint32_t BlobSizeTest::MEDIUM_SIZE;
 constexpr uint32_t BlobSizeTest::LARGE_SIZE;
@@ -66,16 +65,16 @@ TEST_F(BlobSizeTest, ResizingToItself_Large) {
 
 TEST_F(BlobSizeTest, EmptyBlobStaysEmptyWhenLoading) {
   Key key = blob->key();
-  blob.reset();
-  auto loaded = blobStore->load(key);
+  reset(std::move(blob));
+  auto loaded = loadBlob(key);
   EXPECT_EQ(0, loaded->size());
 }
 
 TEST_F(BlobSizeTest, BlobSizeStaysIntactWhenLoading) {
   blob->resize(LARGE_SIZE);
   Key key = blob->key();
-  blob.reset();
-  auto loaded = blobStore->load(key);
+  reset(std::move(blob));
+  auto loaded = loadBlob(key);
   EXPECT_EQ(LARGE_SIZE, loaded->size());
 }
 
@@ -114,7 +113,7 @@ TEST_F(BlobSizeTest, WritingAfterEndOfBlobGrowsBlob_NonEmpty) {
 
 TEST_F(BlobSizeTest, ChangingSizeImmediatelyFlushes) {
   blob->resize(LARGE_SIZE);
-  auto loaded = blobStore->load(blob->key());
+  auto loaded = loadBlob(blob->key());
   EXPECT_EQ(LARGE_SIZE, loaded->size());
 }
 
@@ -143,7 +142,7 @@ TEST_F(BlobSizeDataTest, BlobIsZeroedOutAfterGrowing) {
 
 TEST_F(BlobSizeDataTest, BlobIsZeroedOutAfterGrowingAndLoading) {
   blob->resize(LARGE_SIZE);
-  auto loaded = blobStore->load(blob->key());
+  auto loaded = loadBlob(blob->key());
   EXPECT_EQ(0, std::memcmp(readBlob(*loaded).data(), ZEROES.data(), LARGE_SIZE)); 
 }
 
diff --git a/test/implementations/onblocks/BlobStoreTest.cpp b/test/implementations/onblocks/BlobStoreTest.cpp
index cff3eb6e..7481fdaf 100644
--- a/test/implementations/onblocks/BlobStoreTest.cpp
+++ b/test/implementations/onblocks/BlobStoreTest.cpp
@@ -1,16 +1,29 @@
 #include "testutils/BlobStoreTest.h"
+#include <boost/optional/optional_io.hpp>
 
 using blockstore::Key;
+using cpputils::unique_ref;
+using blobstore::Blob;
+using boost::none;
+
+
+//gtest/boost::optional workaround for working with optional<unique_ref<T>>
+namespace boost {
+  std::ostream& operator<<(std::ostream& out, const unique_ref<Blob> &ref) {
+    out << "[" << ref->key().ToString() << "]" << ref.get();
+    return out;
+  }
+}
 
 TEST_F(BlobStoreTest, LoadNonexistingKeyOnEmptyBlobstore) {
   const blockstore::Key key = blockstore::Key::FromString("1491BB4932A389EE14BC7090AC772972");
-  EXPECT_EQ(nullptr, blobStore->load(key));
+  EXPECT_EQ(none, blobStore->load(key));
 }
 
 TEST_F(BlobStoreTest, LoadNonexistingKeyOnNonEmptyBlobstore) {
   blobStore->create();
   const blockstore::Key key = blockstore::Key::FromString("1491BB4932A389EE14BC7090AC772972");
-  EXPECT_EQ(nullptr, blobStore->load(key));
+  EXPECT_EQ(none, blobStore->load(key));
 }
 
 TEST_F(BlobStoreTest, TwoCreatedBlobsHaveDifferentKeys) {
@@ -23,13 +36,13 @@ TEST_F(BlobStoreTest, BlobIsNotLoadableAfterDeletion_DeleteDirectly) {
   auto blob = blobStore->create();
   Key key = blob->key();
   blobStore->remove(std::move(blob));
-  EXPECT_EQ(nullptr, blobStore->load(key).get());
+  EXPECT_FALSE((bool)blobStore->load(key));
 }
 
 TEST_F(BlobStoreTest, BlobIsNotLoadableAfterDeletion_DeleteAfterLoading) {
   auto blob = blobStore->create();
   Key key = blob->key();
-  blob.reset();
-  blobStore->remove(blobStore->load(key));
-  EXPECT_EQ(nullptr, blobStore->load(key).get());
+  reset(std::move(blob));
+  blobStore->remove(loadBlob(key));
+  EXPECT_FALSE((bool)blobStore->load(key));
 }
diff --git a/test/implementations/onblocks/testutils/BlobStoreTest.h b/test/implementations/onblocks/testutils/BlobStoreTest.h
index d81a9369..2c664646 100644
--- a/test/implementations/onblocks/testutils/BlobStoreTest.h
+++ b/test/implementations/onblocks/testutils/BlobStoreTest.h
@@ -9,4 +9,15 @@ public:
   static constexpr uint32_t BLOCKSIZE_BYTES = 4096;
 
   std::unique_ptr<blobstore::BlobStore> blobStore;
+
+  cpputils::unique_ref<blobstore::Blob> loadBlob(const blockstore::Key &key) {
+    auto loaded = blobStore->load(key);
+    EXPECT_TRUE((bool)loaded);
+    return std::move(*loaded);
+  }
+
+  void reset(cpputils::unique_ref<blobstore::Blob> ref) {
+    UNUSED(ref);
+    //ref is moved into here and then destructed
+  }
 };