diff --git a/cmd/moncheck/main.go b/cmd/moncheck/main.go
index 62a1551..6aa34a5 100644
--- a/cmd/moncheck/main.go
+++ b/cmd/moncheck/main.go
@@ -145,8 +145,11 @@ func check(thread int, db *sql.DB, waitDuration, timeout time.Duration, hostname
 		msg := output.String()
 
 		if _, err := tx.Exec(`update active_checks ac
-		set next_time = now() + intval, states = ARRAY[$2::int] || states[1:4], msg = $3, acknowledged = case when $4 then false else acknowledged end
-where check_id = $1`, id, &state, &msg, states.ToOK()); err != nil {
+		set next_time = now() + intval, states = ARRAY[$2::int] || states[1:4],
+				msg = $3,
+				acknowledged = case when $4 then false else acknowledged end,
+				state_since = case $2 when states[1] then state_since else now() end
+			where check_id = $1`, id, &state, &msg, states.ToOK()); err != nil {
 			log.Printf("[%d] could not update row '%d': %s", thread, id, err)
 			tx.Rollback()
 			continue
@@ -158,6 +161,7 @@ where check_id = $1`, id, &state, &msg, states.ToOK()); err != nil {
 			join checks_notify cn on ac.check_id = cn.check_id
 			join mapping_level ml on ac.mapping_id = ml.mapping_id and s.s = ml.source
 			where ac.check_id = $1
+				and ac.acknowledged = false
 			group by cn.notifier_id;`, &id, &msg, &mapId, &hostname); err != nil {
 			log.Printf("[%d] could not create notification for '%d': %s", thread, id, err)
 			tx.Rollback()