diff --git a/piker/data/__init__.py b/piker/data/__init__.py
index afc74d75..907dd6fe 100644
--- a/piker/data/__init__.py
+++ b/piker/data/__init__.py
@@ -53,9 +53,10 @@ from ._sharedmem import (
 )
 from ._source import base_iohlc_dtype, Symbol
 from ._buffer import (
+    _shms,
+    _incrementers,
     increment_ohlc_buffer,
-    subscribe_ohlc_for_increment,
-    shm_incrementing,
+    iter_ohlc_periods,
 )
 
 __all__ = [
@@ -64,7 +65,7 @@ __all__ = [
     'attach_shm_array',
     'open_shm_array',
     'get_shm_token',
-    'subscribe_ohlc_for_increment',
+    # 'subscribe_ohlc_for_increment',
 ]
 
 
@@ -181,10 +182,10 @@ async def allocate_persistent_feed(
         readonly=False,
     )
 
-    # assert opened
-    if not opened:
-        # do history validation?
-        pass
+    # do history validation?
+    assert opened, "Persistent shm for sym was already open?!"
+    # if not opened:
+    #     raise RuntimeError("Persistent shm for sym was already open?!")
 
     send, quote_stream = trio.open_memory_channel(2**8)
     feed_is_live = trio.Event()
@@ -204,34 +205,48 @@ async def allocate_persistent_feed(
 
     init_msg[symbol]['shm_token'] = shm.token
     cs = trio.CancelScope()
+
+    # TODO: make this into a composed type which also
+    # contains the backfiller cs for individual super-based
+    # resspawns when needed.
     bus.feeds[symbol] = (cs, init_msg, first_quote)
 
     with cs:
         if opened:
-            # start history backfill task
-            # ``backfill_bars()`` is a required backend func
-            await bus.nursery.start(mod.backfill_bars, symbol, shm)
 
-        # yield back control to starting nursery
-        task_status.started((init_msg,  first_quote))
+            # start history backfill task ``backfill_bars()`` is
+            # a required backend func this must block until shm is
+            # filled with first set of ohlc bars
+            await bus.nursery.start(mod.backfill_bars, symbol, shm)
 
         times = shm.array['time']
         delay_s = times[-1] - times[times != times[-1]][-1]
 
+        # pass OHLC sample rate in seconds
+        init_msg[symbol]['sample_rate'] = delay_s
+
+        # yield back control to starting nursery
+        task_status.started((init_msg,  first_quote))
+
         await feed_is_live.wait()
 
-        # tell incrementer task it can start
-        shm_incrementing(shm.token['shm_name']).set()
+        # # tell incrementer task it can start
+        # shm_incrementing(shm.token['shm_name']).set()
 
         # start shm incrementingn for OHLC sampling
-        subscribe_ohlc_for_increment(shm, delay_s)
+        # subscribe_ohlc_for_increment(shm, delay_s)
 
-        # begin shm write loop and broadcast to subscribers
+        if opened:
+            _shms.setdefault(delay_s, []).append(shm)
+
+            if _incrementers.get(delay_s) is None:
+                cs = await bus.nursery.start(increment_ohlc_buffer, delay_s)
 
         sum_tick_vlm: bool = init_msg.get(
             'shm_write_opts', {}
         ).get('sum_tick_vlm', True)
 
+        # begin shm write loop and broadcast to subscribers
         async with quote_stream:
 
             log.info("Started shared mem bar writer")
@@ -372,6 +387,7 @@ class Feed:
     _brokerd_portal: tractor._portal.Portal
     _index_stream: Optional[AsyncIterator[int]] = None
     _trade_stream: Optional[AsyncIterator[Dict[str, Any]]] = None
+    _max_sample_rate: int = 0
 
     # cache of symbol info messages received as first message when
     # a stream startsc.
@@ -380,15 +396,19 @@ class Feed:
     async def receive(self) -> dict:
         return await self.stream.__anext__()
 
-    async def index_stream(self) -> AsyncIterator[int]:
+    async def index_stream(
+        self,
+        delay_s: Optional[int] = None
+
+    ) -> AsyncIterator[int]:
+
         if not self._index_stream:
             # XXX: this should be singleton on a host,
             # a lone broker-daemon per provider should be
             # created for all practical purposes
             self._index_stream = await self._brokerd_portal.run(
-                increment_ohlc_buffer,
-                shm_token=self.shm.token,
-                topics=['index'],
+                iter_ohlc_periods,
+                delay_s=delay_s or self._max_sample_rate,
             )
 
         return self._index_stream
@@ -459,9 +479,9 @@ async def open_feed(
             loglevel=loglevel,
         )
 
-        # TODO: we can't do this **and** be compate with
-        # ``tractor.msg.pub``, should we maybe just drop this after
-        # tests are in?
+        # TODO: can we make this work better with the proposed
+        # context based bidirectional streaming style api proposed in:
+        # https://github.com/goodboy/tractor/issues/53
         init_msg = await stream.receive()
 
         shm = attach_shm_array(
@@ -478,10 +498,12 @@ async def open_feed(
             mod=mod,
             _brokerd_portal=portal,
         )
+        ohlc_sample_rates = []
 
         for sym, data in init_msg.items():
 
             si = data['symbol_info']
+            ohlc_sample_rates.append(data['sample_rate'])
 
             symbol = Symbol(
                 key=sym,
@@ -493,9 +515,11 @@ async def open_feed(
 
             feed.symbols[sym] = symbol
 
+            # cast shm dtype to list... can't member why we need this
             shm_token = data['shm_token']
+            shm_token['dtype_descr'] = list(shm_token['dtype_descr'])
+            assert shm_token == shm.token  # sanity
 
-        shm_token['dtype_descr'] = list(shm_token['dtype_descr'])
-        assert shm_token == shm.token  # sanity
+        feed._max_sample_rate = max(ohlc_sample_rates)
 
         yield feed