diff --git a/bin/effecteval b/bin/effecteval
--- a/bin/effecteval
+++ b/bin/effecteval
@@ -31,21 +31,21 @@ class EffectEdit(PrettyErrorHandler, cyc
         self.settings.graph.patch(Patch(delQuads=[
             (song, L9['effect'], uri, ctx),
             ]))
-
+        
 class SongEffects(PrettyErrorHandler, cyclone.web.RequestHandler):
     def post(self):
         song = URIRef(self.get_argument('uri'))
         drop = URIRef(self.get_argument('drop'))
         ctx = song
-        now = time.time()
-        effect = song + "/effect/e-%f" % now
-        curve = song + "/curve/c-%f" % now
+        graph = self.settings.graph
+        effect = graph.sequentialUri(song + "/effect/e-")
+        curve = graph.sequentialUri(song + "/curve/c-")
 
-        with self.settings.graph.currentState(
+        with graph.currentState(
                 tripleFilter=(drop, RDFS.label, None)) as g:
             dropSubLabel = g.label(drop)
         
-        self.settings.graph.patch(Patch(addQuads=[
+        graph.patch(Patch(addQuads=[
             (song, L9['curve'], curve, ctx),
             (song, L9['effect'], effect, ctx),
             (effect, RDF.type, L9['Effect'], ctx),
diff --git a/light9/rdfdb/currentstategraphapi.py b/light9/rdfdb/currentstategraphapi.py
--- a/light9/rdfdb/currentstategraphapi.py
+++ b/light9/rdfdb/currentstategraphapi.py
@@ -1,4 +1,4 @@
-import logging, traceback, time
+import logging, traceback, time, itertools
 from rdflib import ConjunctiveGraph
 from light9.rdfdb.rdflibpatch import contextsForStatement as rp_contextsForStatement
 log = logging.getLogger("currentstate")
@@ -48,6 +48,18 @@ class CurrentStateGraphApi(object):
 
         return Mgr()
 
+    def sequentialUri(self, prefix):
+        """
+        Prefix URIRef like http://example.com/r- will return
+        http://example.com/r-1 if that uri is not a subject in the graph,
+        or else http://example.com/r-2, etc
+        """
+        for i in itertools.count(1):
+            newUri = prefix + str(i)
+            if not list(self._grap.triples((newUri, None, None))):
+                return newUri
+
+        
 def contextsForStatementNoWildcards(g, triple):
     if None in triple:
         raise NotImplementedError("no wildcards")