diff --git a/src/Jobs/Crontab.hs b/src/Jobs/Crontab.hs
index 6605f42d5..aebc11ad1 100644
--- a/src/Jobs/Crontab.hs
+++ b/src/Jobs/Crontab.hs
@@ -162,54 +162,57 @@ determineCrontab = execWriterT $ do
 
   let
     sheetJobs (Entity nSheet Sheet{..}) = do
-      for_ sheetActiveFrom $ \aFrom -> 
+      for_ (max <$> sheetVisibleFrom <*> sheetActiveFrom) $ \aFrom -> 
         tell $ HashMap.singleton
           (JobCtlQueue $ JobQueueNotification NotificationSheetActive{..})
           Cron
-            { cronInitial = CronTimestamp . utcToLocalTimeTZ appTZ $ maybe id max sheetVisibleFrom aFrom
-            , cronRepeat = CronRepeatOnChange
+            { cronInitial = CronTimestamp $ utcToLocalTimeTZ appTZ aFrom
+            , cronRepeat = CronRepeatNever
             , cronRateLimit = appNotificationRateLimit
             , cronNotAfter = maybe (Left appNotificationExpiration) (Right . CronTimestamp . utcToLocalTimeTZ appTZ) sheetActiveTo
             }
-      for_ sheetHintFrom $ \hFrom -> maybeT (return ()) $ do
+      for_ (max <$> sheetVisibleFrom <*> sheetHintFrom) $ \hFrom -> maybeT (return ()) $ do
         guard $ maybe True (\aFrom -> abs (diffUTCTime aFrom hFrom) > 300) sheetActiveFrom
+        guardM $ or2M (return $ maybe True (\sFrom -> abs (diffUTCTime sFrom hFrom) > 300) sheetSolutionFrom)
+                      (fmap not . lift . lift $ exists [SheetFileType ==. SheetSolution, SheetFileSheet ==. nSheet])
         guardM . lift . lift $ exists [SheetFileType ==. SheetHint, SheetFileSheet ==. nSheet]
         tell $ HashMap.singleton
           (JobCtlQueue $ JobQueueNotification NotificationSheetHint{..})
           Cron
-            { cronInitial = CronTimestamp . utcToLocalTimeTZ appTZ $ maybe id max sheetVisibleFrom hFrom
-            , cronRepeat = CronRepeatOnChange
+            { cronInitial = CronTimestamp $ utcToLocalTimeTZ appTZ hFrom
+            , cronRepeat = CronRepeatNever
             , cronRateLimit = appNotificationRateLimit
-            , cronNotAfter = Left appNotificationExpiration
+            , cronNotAfter = maybe (Left appNotificationExpiration) (Right . CronTimestamp . utcToLocalTimeTZ appTZ) sheetActiveTo
             }
-      for_ sheetSolutionFrom $ \hFrom -> maybeT (return ()) $ do
-        guard $ maybe True (\aFrom -> abs (diffUTCTime aFrom hFrom) > 300) sheetActiveFrom
+      for_ (max <$> sheetVisibleFrom <*> sheetSolutionFrom) $ \sFrom -> maybeT (return ()) $ do
+        guard $ maybe True (\aFrom -> abs (diffUTCTime aFrom sFrom) > 300) sheetActiveFrom
         guardM . lift . lift $ exists [SheetFileType ==. SheetSolution, SheetFileSheet ==. nSheet]
         tell $ HashMap.singleton
           (JobCtlQueue $ JobQueueNotification NotificationSheetSolution{..})
           Cron
-            { cronInitial = CronTimestamp . utcToLocalTimeTZ appTZ $ maybe id max sheetVisibleFrom hFrom
-            , cronRepeat = CronRepeatOnChange
+            { cronInitial = CronTimestamp $ utcToLocalTimeTZ appTZ sFrom
+            , cronRepeat = CronRepeatNever
             , cronRateLimit = appNotificationRateLimit
-            , cronNotAfter = Left appNotificationExpiration
+            , cronNotAfter = Left nominalDay
             }
       for_ sheetActiveTo $ \aTo -> do
-        tell $ HashMap.singleton
-          (JobCtlQueue $ JobQueueNotification NotificationSheetSoonInactive{..})
-          Cron
-            { cronInitial = CronTimestamp . utcToLocalTimeTZ appTZ . maybe id max sheetActiveFrom . maybe id max sheetVisibleFrom $ addUTCTime (-nominalDay) aTo
-            , cronRepeat = CronRepeatOnChange -- Allow repetition of the notification (if something changes), but wait at least an hour
-            , cronRateLimit = appNotificationRateLimit
-            , cronNotAfter = Right . CronTimestamp $ utcToLocalTimeTZ appTZ aTo
-            }
-        tell $ HashMap.singleton
-          (JobCtlQueue $ JobQueueNotification NotificationSheetInactive{..})
-          Cron
-            { cronInitial   = CronTimestamp . utcToLocalTimeTZ appTZ $ maybe id max sheetVisibleFrom aTo
-            , cronRepeat    = CronRepeatOnChange
-            , cronRateLimit = appNotificationRateLimit
-            , cronNotAfter  = Left appNotificationExpiration
-            }             
+        whenIsJust (max aTo <$> sheetVisibleFrom) $ \aTo' -> do
+          tell $ HashMap.singleton
+            (JobCtlQueue $ JobQueueNotification NotificationSheetSoonInactive{..})
+            Cron
+              { cronInitial = CronTimestamp . utcToLocalTimeTZ appTZ . maybe id max sheetActiveFrom $ addUTCTime (-nominalDay) aTo'
+              , cronRepeat = CronRepeatOnChange -- Allow repetition of the notification (if something changes), but wait at least an hour
+              , cronRateLimit = appNotificationRateLimit
+              , cronNotAfter = Right . CronTimestamp $ utcToLocalTimeTZ appTZ aTo
+              }
+          tell $ HashMap.singleton
+            (JobCtlQueue $ JobQueueNotification NotificationSheetInactive{..})
+            Cron
+              { cronInitial   = CronTimestamp $ utcToLocalTimeTZ appTZ aTo
+              , cronRepeat    = CronRepeatOnChange
+              , cronRateLimit = appNotificationRateLimit
+              , cronNotAfter  = Left appNotificationExpiration
+              }             
         when sheetAutoDistribute $
           tell $ HashMap.singleton
             (JobCtlQueue $ JobDistributeCorrections nSheet)
diff --git a/src/Jobs/Handler/QueueNotification.hs b/src/Jobs/Handler/QueueNotification.hs
index 11d3d15d0..29b078816 100644
--- a/src/Jobs/Handler/QueueNotification.hs
+++ b/src/Jobs/Handler/QueueNotification.hs
@@ -15,82 +15,82 @@ import qualified Data.Set as Set
 import Handler.Utils.ExamOffice.Exam
 import Handler.Utils.ExamOffice.ExternalExam
 
+import qualified Data.Conduit.Combinators as C
+
 
 dispatchJobQueueNotification :: Notification -> JobHandler UniWorX
 dispatchJobQueueNotification jNotification = JobHandlerAtomic $ do
-  candidates <- hoist lift $ determineNotificationCandidates jNotification
   nClass <- hoist lift $ classifyNotification jNotification
-  mapM_ (queueDBJob . flip JobSendNotification jNotification) $ do
-    Entity uid User{userNotificationSettings} <- candidates
-    guard $ notificationAllowed userNotificationSettings nClass
-    return uid
+  runConduit $ transPipe (hoist lift) (determineNotificationCandidates jNotification)
+            .| C.filter (\(Entity _ User{userNotificationSettings}) -> notificationAllowed userNotificationSettings nClass)
+            .| C.map (flip JobSendNotification jNotification . entityKey) .| sinkDBJobs
 
 
-determineNotificationCandidates :: Notification -> DB [Entity User]
+determineNotificationCandidates :: Notification -> ConduitT () (Entity User) DB ()
 determineNotificationCandidates NotificationSubmissionRated{..}
-  = E.select . E.from $ \(user `E.InnerJoin` submissionUser) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` submissionUser) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ user E.^. UserId E.==. submissionUser E.^. SubmissionUserUser
       E.where_ $ submissionUser E.^. SubmissionUserSubmission E.==. E.val nSubmission
       return user
 determineNotificationCandidates NotificationSheetActive{..}
-  = E.select . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ sheet E.^. SheetCourse E.==. courseParticipant E.^. CourseParticipantCourse
       E.on $ user E.^. UserId E.==. courseParticipant E.^. CourseParticipantUser
       E.where_ $ courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
       E.where_ $ sheet E.^. SheetId E.==. E.val nSheet
       return user
 determineNotificationCandidates NotificationSheetHint{..}
-  = E.select . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ sheet E.^. SheetCourse E.==. courseParticipant E.^. CourseParticipantCourse
       E.on $ user E.^. UserId E.==. courseParticipant E.^. CourseParticipantUser
       E.where_ $ courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
       E.where_ $ sheet E.^. SheetId E.==. E.val nSheet
       return user
 determineNotificationCandidates NotificationSheetSolution{..}
-  = E.select . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ sheet E.^. SheetCourse E.==. courseParticipant E.^. CourseParticipantCourse
       E.on $ user E.^. UserId E.==. courseParticipant E.^. CourseParticipantUser
       E.where_ $ courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
       E.where_ $ sheet E.^. SheetId E.==. E.val nSheet
       return user
 determineNotificationCandidates NotificationSheetSoonInactive{..}
-  = E.select . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` courseParticipant `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ sheet E.^. SheetCourse E.==. courseParticipant E.^. CourseParticipantCourse
       E.on $ user E.^. UserId E.==. courseParticipant E.^. CourseParticipantUser
       E.where_ $ courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
       E.where_ $ sheet E.^. SheetId E.==. E.val nSheet
       return user
 determineNotificationCandidates NotificationSheetInactive{..}
-  = E.select . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ lecturer E.^. LecturerCourse E.==. sheet E.^. SheetCourse
       E.on $ lecturer E.^. LecturerUser   E.==. user E.^. UserId
       E.where_ $ sheet E.^. SheetId E.==. E.val nSheet
       return user
 determineNotificationCandidates NotificationCorrectionsAssigned{..}
-  = selectList [UserId ==. nUser] []
+  = selectSource [UserId ==. nUser] []
 determineNotificationCandidates NotificationCorrectionsNotDistributed{nSheet}
-  = E.select . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  = E.selectSource . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` sheet) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
       E.on $ lecturer E.^. LecturerCourse E.==. sheet E.^. SheetCourse
       E.on $ lecturer E.^. LecturerUser E.==. user E.^. UserId
       E.where_ $ sheet E.^. SheetId E.==. E.val nSheet
       return user
 determineNotificationCandidates NotificationUserRightsUpdate{..} = do
   -- always send to affected user
-  affectedUser <- selectList [UserId ==. nUser] []
+  affectedUser <- lift $ selectList [UserId ==. nUser] []
   -- send to same-school admins only if there was an update
-  currentAdminSchools <- setOf (folded . _entityVal . _userFunctionSchool) <$> selectList [UserFunctionUser ==. nUser, UserFunctionFunction ==. SchoolAdmin] []
+  currentAdminSchools <- lift $ setOf (folded . _entityVal . _userFunctionSchool) <$> selectList [UserFunctionUser ==. nUser, UserFunctionFunction ==. SchoolAdmin] []
   let oldAdminSchools = setOf (folded . filtered ((== SchoolAdmin) . view _1) . _2 . from _SchoolId) nOriginalRights
       newAdminSchools = currentAdminSchools `Set.difference` oldAdminSchools
-  affectedAdmins <- E.select . E.from $ \(user `E.InnerJoin` admin) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  affectedAdmins <- lift . E.select . E.from $ \(user `E.InnerJoin` admin) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
     E.on $ admin E.^. UserFunctionUser E.==. user E.^. UserId
     E.where_ $ admin E.^. UserFunctionSchool `E.in_` E.valList (Set.toList newAdminSchools)
          E.&&. admin E.^. UserFunctionFunction E.==. E.val SchoolAdmin
     return user
-  return . nub $ affectedUser <> affectedAdmins
+  yieldMany . nub $ affectedUser <> affectedAdmins
 determineNotificationCandidates NotificationUserAuthModeUpdate{..}
-  = selectList [UserId ==. nUser] []
+  = selectSource [UserId ==. nUser] []
 determineNotificationCandidates NotificationExamRegistrationActive{..} =
-  E.select . E.from $ \(exam `E.InnerJoin` courseParticipant `E.InnerJoin` user) -> do
+  E.selectSource . E.from $ \(exam `E.InnerJoin` courseParticipant `E.InnerJoin` user) -> do
     E.on $ courseParticipant E.^. CourseParticipantUser E.==. user E.^. UserId
     E.on $ courseParticipant E.^. CourseParticipantCourse E.==. exam E.^. ExamCourse
     E.where_ $ exam E.^. ExamId E.==. E.val nExam
@@ -100,7 +100,7 @@ determineNotificationCandidates NotificationExamRegistrationActive{..} =
     E.where_ $ courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
     return user
 determineNotificationCandidates NotificationExamRegistrationSoonInactive{..} =
-  E.select . E.from $ \(exam `E.InnerJoin` courseParticipant `E.InnerJoin` user) -> do
+  E.selectSource . E.from $ \(exam `E.InnerJoin` courseParticipant `E.InnerJoin` user) -> do
     E.on $ courseParticipant E.^. CourseParticipantUser E.==. user E.^. UserId
     E.on $ courseParticipant E.^. CourseParticipantCourse E.==. exam E.^. ExamCourse
     E.where_ $ exam E.^. ExamId E.==. E.val nExam
@@ -110,21 +110,21 @@ determineNotificationCandidates NotificationExamRegistrationSoonInactive{..} =
     E.where_ $ courseParticipant E.^. CourseParticipantState E.==. E.val CourseParticipantActive
     return user
 determineNotificationCandidates NotificationExamDeregistrationSoonInactive{..} =
-  E.select . E.from $ \(examRegistration `E.InnerJoin` user) -> do
+  E.selectSource . E.from $ \(examRegistration `E.InnerJoin` user) -> do
     E.on $ examRegistration E.^. ExamRegistrationUser E.==. user E.^. UserId
     E.where_ $ examRegistration E.^. ExamRegistrationExam E.==. E.val nExam
     return user
 determineNotificationCandidates notif@NotificationExamResult{..} = do
-  lastExec <- fmap (fmap $ cronLastExecTime . entityVal) . getBy . UniqueCronLastExec . toJSON $ JobQueueNotification notif
-  E.select . E.from $ \(examResult `E.InnerJoin` user) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  lastExec <- lift . fmap (fmap $ cronLastExecTime . entityVal) . getBy . UniqueCronLastExec . toJSON $ JobQueueNotification notif
+  E.selectSource . E.from $ \(examResult `E.InnerJoin` user) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
     E.on $ examResult E.^. ExamResultUser E.==. user E.^. UserId
     E.where_ $ examResult E.^. ExamResultExam E.==. E.val nExam
     whenIsJust lastExec $ \lastExec' ->
       E.where_ $ examResult E.^. ExamResultLastChanged E.>. E.val lastExec'
     return user
 determineNotificationCandidates NotificationAllocationStaffRegister{..} = do
-  Allocation{..} <- getJust nAllocation
-  E.select . E.from $ \(user `E.InnerJoin` userFunction) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  Allocation{..} <- lift $ getJust nAllocation
+  E.selectSource . E.from $ \(user `E.InnerJoin` userFunction) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
     E.on $ user E.^. UserId E.==. userFunction E.^. UserFunctionUser
      E.&&. userFunction E.^. UserFunctionSchool E.==. E.val allocationSchool
      E.&&. userFunction E.^. UserFunctionFunction E.==. E.val SchoolLecturer
@@ -143,7 +143,7 @@ determineNotificationCandidates NotificationAllocationStaffRegister{..} = do
 
     return user
 determineNotificationCandidates NotificationAllocationAllocation{..} =
-  E.select . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` course `E.InnerJoin` allocationCourse) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  E.selectSource . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` course `E.InnerJoin` allocationCourse) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
     E.on $ allocationCourse E.^. AllocationCourseCourse E.==. course E.^. CourseId
      E.&&. allocationCourse E.^. AllocationCourseAllocation E.==. E.val nAllocation
     E.on $ course E.^. CourseId E.==. lecturer E.^. LecturerCourse
@@ -162,7 +162,7 @@ determineNotificationCandidates NotificationAllocationAllocation{..} =
 
     return user
 determineNotificationCandidates NotificationAllocationUnratedApplications{..} =
-  E.select . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` course `E.InnerJoin` allocationCourse) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  E.selectSource . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` course `E.InnerJoin` allocationCourse) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
     E.on $ allocationCourse E.^. AllocationCourseCourse E.==. course E.^. CourseId
      E.&&. allocationCourse E.^. AllocationCourseAllocation E.==. E.val nAllocation
     E.on $ course E.^. CourseId E.==. lecturer E.^. LecturerCourse
@@ -176,8 +176,8 @@ determineNotificationCandidates NotificationAllocationUnratedApplications{..} =
 
     return user
 determineNotificationCandidates NotificationAllocationRegister{..} = do
-  Allocation{..} <- getJust nAllocation
-  E.select . E.from $ \user -> do
+  Allocation{..} <- lift $ getJust nAllocation
+  E.selectSource . E.from $ \user -> do
     E.where_ . E.exists . E.from $ \userSchool ->
       E.where_ $ userSchool E.^. UserSchoolUser E.==. user E.^. UserId
            E.&&. userSchool E.^. UserSchoolSchool E.==. E.val allocationSchool
@@ -189,7 +189,7 @@ determineNotificationCandidates NotificationAllocationRegister{..} = do
 
     return user
 determineNotificationCandidates NotificationAllocationOutdatedRatings{..} =
-  E.select . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` course `E.InnerJoin` allocationCourse) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
+  E.selectSource . E.from $ \(user `E.InnerJoin` lecturer `E.InnerJoin` course `E.InnerJoin` allocationCourse) -> E.distinctOnOrderBy [E.asc $ user E.^. UserId] $ do
     E.on $ allocationCourse E.^. AllocationCourseCourse E.==. course E.^. CourseId
      E.&&. allocationCourse E.^. AllocationCourseAllocation E.==. E.val nAllocation
     E.on $ course E.^. CourseId E.==. lecturer E.^. LecturerCourse
@@ -203,26 +203,26 @@ determineNotificationCandidates NotificationAllocationOutdatedRatings{..} =
 
     return user
 determineNotificationCandidates NotificationExamOfficeExamResults{..} =
-  E.select . E.from $ \user -> do
+  E.selectSource . E.from $ \user -> do
     E.where_ . E.exists . E.from $ \examResult -> do
       E.where_ $ examResult E.^. ExamResultExam E.==. E.val nExam
       E.where_ $ examOfficeExamResultAuth (user E.^. UserId) examResult
     return user
 determineNotificationCandidates NotificationExamOfficeExamResultsChanged{..} =
-  E.select . E.from $ \user -> do
+  E.selectSource . E.from $ \user -> do
     E.where_ . E.exists . E.from $ \examResult -> do
       E.where_ $ examResult E.^. ExamResultId `E.in_` E.valList (Set.toList nExamResults)
       E.where_ $ examOfficeExamResultAuth (user E.^. UserId) examResult
     return user
 determineNotificationCandidates NotificationExamOfficeExternalExamResults{..} =
-  E.select . E.from $ \user -> do
+  E.selectSource . E.from $ \user -> do
     E.where_ . E.exists . E.from $ \externalExamResult -> do
       E.where_ $ externalExamResult E.^. ExternalExamResultExam E.==. E.val nExternalExam
       E.where_ $ examOfficeExternalExamResultAuth (user E.^. UserId) externalExamResult
     return user
 determineNotificationCandidates notif@NotificationAllocationResults{..} = do
-  lastExec <- fmap (fmap $ cronLastExecTime . entityVal) . getBy . UniqueCronLastExec . toJSON $ JobQueueNotification notif
-  E.select . E.from $ \user -> do
+  lastExec <- lift . fmap (fmap $ cronLastExecTime . entityVal) . getBy . UniqueCronLastExec . toJSON $ JobQueueNotification notif
+  E.selectSource . E.from $ \user -> do
     let isStudent = E.exists . E.from $ \application ->
           E.where_ $ application E.^. CourseApplicationAllocation E.==. E.just (E.val nAllocation)
                E.&&. application E.^. CourseApplicationUser E.==. user E.^. UserId
@@ -248,17 +248,17 @@ determineNotificationCandidates notif@NotificationAllocationResults{..} = do
 
     return user
 determineNotificationCandidates NotificationCourseRegistered{..} =
-  maybeToList <$> getEntity nUser
+  yieldMMany $ getEntity nUser
 determineNotificationCandidates NotificationSubmissionEdited{..} =
-  E.select . E.from $ \(user `E.InnerJoin` submissionUser) -> do
+  E.selectSource . E.from $ \(user `E.InnerJoin` submissionUser) -> do
     E.on $ user E.^. UserId E.==. submissionUser E.^. SubmissionUserUser
     E.where_ $ submissionUser E.^. SubmissionUserSubmission E.==. E.val nSubmission
          E.&&. user E.^. UserId E.!=. E.val nInitiator
     return user
 determineNotificationCandidates NotificationSubmissionUserCreated{..} =
-  maybeToList <$> getEntity nUser
+  yieldMMany $ getEntity nUser
 determineNotificationCandidates NotificationSubmissionUserDeleted{..} =
-  maybeToList <$> getEntity nUser
+  yieldMMany $ getEntity nUser
 
 
 classifyNotification :: Notification -> DB NotificationTrigger
diff --git a/src/Utils.hs b/src/Utils.hs
index da20821a1..94b1b4426 100644
--- a/src/Utils.hs
+++ b/src/Utils.hs
@@ -43,7 +43,8 @@ import qualified Data.List as List
 import qualified Data.HashMap.Strict as HashMap
 import qualified Data.Vector as V
 
-import qualified Data.Conduit.List as C
+-- import qualified Data.Conduit.List as C
+import qualified Data.Conduit.Combinators as C
 
 import Control.Lens
 import Control.Lens as Utils (none)
@@ -815,6 +816,9 @@ anyMC, allMC :: forall a o m. Monad m => (a -> m Bool) -> ConduitT a o m Bool
 anyMC f = C.mapM f .| orC
 allMC f = C.mapM f .| andC
 
+yieldMMany :: forall mono m a. (Monad m, MonoFoldable mono) => m mono -> ConduitT a (Element mono) m ()
+yieldMMany = C.yieldMany <=< lift
+
 -----------------
 -- Alternative --
 -----------------
diff --git a/test/Database/Fill.hs b/test/Database/Fill.hs
index d70a39306..6e5f2ac55 100644
--- a/test/Database/Fill.hs
+++ b/test/Database/Fill.hs
@@ -819,8 +819,8 @@ fillDb = do
       , sheetVisibleFrom = Just $ termTime True Summer prog False Monday toMidnight
       , sheetActiveFrom = Just $ termTime True Summer (prog + 1) False Monday toMidnight
       , sheetActiveTo = Just $ termTime True Summer (prog + 2) False Sunday beforeMidnight
-      , sheetHintFrom = Nothing
-      , sheetSolutionFrom = Nothing
+      , sheetHintFrom = Just $ termTime True Summer (prog + 1) False Sunday beforeMidnight
+      , sheetSolutionFrom = Just $ termTime True Summer (prog + 2) False Sunday beforeMidnight
       , sheetAutoDistribute = True
       , sheetAnonymousCorrection = True
       }