diff --git a/piker/data/_sampling.py b/piker/data/_sampling.py
index 77b15d7f..428540a8 100644
--- a/piker/data/_sampling.py
+++ b/piker/data/_sampling.py
@@ -37,6 +37,9 @@ if TYPE_CHECKING:
 log = get_logger(__name__)
 
 
+_default_delay_s: float = 1.0
+
+
 class sampler:
     '''
     Global sampling engine registry.
@@ -104,14 +107,18 @@ async def increment_ohlc_buffer(
             # TODO: do we want to support dynamically
             # adding a "lower" lowest increment period?
             await trio.sleep(ad)
-            total_s += lowest
+            total_s += delay_s
 
             # increment all subscribed shm arrays
             # TODO:
             # - this in ``numba``
             # - just lookup shms for this step instead of iterating?
-            for delay_s, shms in sampler.ohlcv_shms.items():
-                if total_s % delay_s != 0:
+            for this_delay_s, shms in sampler.ohlcv_shms.items():
+
+                # short-circuit on any not-ready because slower sample
+                # rate consuming shm buffers.
+                if total_s % this_delay_s != 0:
+                    # print(f'skipping `{this_delay_s}s` sample update')
                     continue
 
                 # TODO: ``numba`` this!
@@ -152,7 +159,6 @@ async def broadcast(
 
     '''
     subs = sampler.subscribers.get(delay_s, ())
-
     first = last = -1
 
     if shm is None: