diff --git a/ipfsconn/ipfshttp/ipfshttp.go b/ipfsconn/ipfshttp/ipfshttp.go
index 42fca330..ba87070a 100644
--- a/ipfsconn/ipfshttp/ipfshttp.go
+++ b/ipfsconn/ipfshttp/ipfshttp.go
@@ -964,7 +964,7 @@ type chanIterator struct {
 	err     error
 
 	seenMu sync.Mutex
-	seen   *multihash.Set
+	seen   map[string]int
 }
 
 func (ci *chanIterator) Name() string {
@@ -975,27 +975,31 @@ func (ci *chanIterator) Name() string {
 }
 
 // return NewBytesFile.
+// This function might and is actually called multiple times for the same node
+// by the multifile Reader to send the multipart.
 func (ci *chanIterator) Node() files.Node {
 	if !ci.current.Cid.Defined() {
 		return nil
 	}
-	logger.Debugf("it.node(): %s", ci.current.Cid)
-	ci.seenMu.Lock()
-	ci.seen.Add(ci.current.Cid.Hash())
-	ci.seenMu.Unlock()
-
-	stats.Record(ci.ctx, observations.BlocksAdded.M(1))
-	stats.Record(ci.ctx, observations.BlocksAddedSize.M(int64(len(ci.current.Data))))
-
+	logger.Debugf("it.Node(): %s", ci.current.Cid)
 	return files.NewBytesFile(ci.current.Data)
 }
 
+// Seen returns whether we have seen a multihash. It keeps count so it will
+// return true as many times as we have seen it.
 func (ci *chanIterator) Seen(c api.Cid) bool {
 	ci.seenMu.Lock()
-	has := ci.seen.Has(c.Cid.Hash())
-	ci.seen.Remove(c.Cid.Hash())
+	n, ok := ci.seen[string(c.Cid.Hash())]
+	logger.Debugf("Seen(): %s, %d, %t", c, n, ok)
+	if ok {
+		if n == 1 {
+			delete(ci.seen, string(c.Cid.Hash()))
+		} else {
+			ci.seen[string(c.Cid.Hash())] = n - 1
+		}
+	}
 	ci.seenMu.Unlock()
-	return has
+	return ok
 }
 
 func (ci *chanIterator) Done() bool {
@@ -1025,9 +1029,20 @@ func (ci *chanIterator) Next() bool {
 	if ci.done {
 		return false
 	}
+
+	seeBlock := func(b api.NodeWithMeta) {
+		ci.seenMu.Lock()
+		ci.seen[string(b.Cid.Hash())]++
+		ci.seenMu.Unlock()
+		stats.Record(ci.ctx, observations.BlocksAdded.M(1))
+		stats.Record(ci.ctx, observations.BlocksAddedSize.M(int64(len(b.Data))))
+
+	}
+
 	if ci.peeked.Cid.Defined() {
 		ci.current = ci.peeked
 		ci.peeked = api.NodeWithMeta{}
+		seeBlock(ci.current)
 		return true
 	}
 	select {
@@ -1040,8 +1055,12 @@ func (ci *chanIterator) Next() bool {
 			ci.done = true
 			return false
 		}
+		// Record that we have seen this block. This has to be done
+		// here, not in Node() as Node() is called multiple times per
+		// block received.
 		logger.Debugf("it.Next() %s", next.Cid)
 		ci.current = next
+		seeBlock(ci.current)
 		return true
 	}
 }
@@ -1084,7 +1103,7 @@ func (ipfs *Connector) BlockStream(ctx context.Context, blocks <-chan api.NodeWi
 	it := &chanIterator{
 		ctx:    ctx,
 		blocks: blocks,
-		seen:   multihash.NewSet(),
+		seen:   make(map[string]int),
 	}
 	dir := &chanDirectory{
 		iterator: it,