diff --git a/fragment.go b/fragment.go
index 930c8e02b..a18c4de61 100644
--- a/fragment.go
+++ b/fragment.go
@@ -189,7 +189,7 @@ func (f *Fragment) Open() error {
 func (f *Fragment) openStorage() error {
 	// Create a roaring bitmap to serve as storage for the slice.
 	if f.storage == nil {
-		f.storage = roaring.NewBitmap()
+		f.storage = roaring.NewBitmapBtree()
 	}
 	// Open the data file to be mmap'd and used as an ops log.
 	file, err := os.OpenFile(f.path, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
diff --git a/roaring/containers_test.go b/roaring/containers_test.go
index 6d155f397..02e998151 100644
--- a/roaring/containers_test.go
+++ b/roaring/containers_test.go
@@ -5,7 +5,8 @@ import (
 )
 
 func TestContainersIterator(t *testing.T) {
-	btc := NewBTreeContainers()
+	//btc := NewBTreeContainers()
+	btc := NewSliceContainers()
 	itr, found := btc.Iterator(0)
 	if found {
 		t.Fatalf("shouldn't have found 0 in empty btc")
diff --git a/roaring/roaring.go b/roaring/roaring.go
index 51f1efe9a..bcef1762c 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -113,6 +113,14 @@ type Bitmap struct {
 
 // NewBitmap returns a Bitmap with an initial set of values.
 func NewBitmap(a ...uint64) *Bitmap {
+	b := &Bitmap{
+		conts: NewSliceContainers(),
+	}
+	b.Add(a...)
+	return b
+}
+
+func NewBitmapBtree(a ...uint64) *Bitmap {
 	b := &Bitmap{
 		conts: NewBTreeContainers(),
 	}
diff --git a/roaring/roaring_test.go b/roaring/roaring_test.go
index f972d8573..48d29c058 100644
--- a/roaring/roaring_test.go
+++ b/roaring/roaring_test.go
@@ -1176,7 +1176,7 @@ const (
 func BenchmarkContainerLinear(b *testing.B) {
 
 	for n := 0; n < b.N; n++ {
-		bm := roaring.NewBitmap()
+		bm := roaring.NewBitmapBtree()
 		for row := uint64(1); row < NumRows; row++ {
 			for col := uint64(1); col < NumColums; col++ {
 				bm.Add(row*pilosa.SliceWidth + (col * MaxContainerVal))
@@ -1187,7 +1187,7 @@ func BenchmarkContainerLinear(b *testing.B) {
 
 func BenchmarkContainerReverse(b *testing.B) {
 	for n := 0; n < b.N; n++ {
-		bm := roaring.NewBitmap()
+		bm := roaring.NewBitmapBtree()
 		for row := NumRows - 1; row >= 1; row-- {
 			for col := NumColums - 1; col >= 1; col-- {
 				bm.Add(row*pilosa.SliceWidth + (col * MaxContainerVal))
@@ -1198,7 +1198,7 @@ func BenchmarkContainerReverse(b *testing.B) {
 
 func BenchmarkContainerColumn(b *testing.B) {
 	for n := 0; n < b.N; n++ {
-		bm := roaring.NewBitmap()
+		bm := roaring.NewBitmapBtree()
 		for col := uint64(1); col < NumColums; col++ {
 			for row := uint64(1); row < NumRows; row++ {
 				bm.Add(row*pilosa.SliceWidth + (col * MaxContainerVal))
@@ -1210,7 +1210,7 @@ func BenchmarkContainerColumn(b *testing.B) {
 func BenchmarkContainerOutsideIn(b *testing.B) {
 	middle := NumRows / uint64(2)
 	for n := 0; n < b.N; n++ {
-		bm := roaring.NewBitmap()
+		bm := roaring.NewBitmapBtree()
 
 		for col := uint64(1); col < NumColums; col++ {
 			for row := uint64(1); row < middle; row++ {
@@ -1224,7 +1224,7 @@ func BenchmarkContainerOutsideIn(b *testing.B) {
 func BenchmarkContainerInsideOut(b *testing.B) {
 	middle := NumRows / uint64(2)
 	for n := 0; n < b.N; n++ {
-		bm := roaring.NewBitmap()
+		bm := roaring.NewBitmapBtree()
 		for col := uint64(1); col < NumColums; col++ {
 			for row := uint64(1); row <= middle; row++ {
 				bm.Add((middle+row)*pilosa.SliceWidth + (col * MaxContainerVal))