diff --git a/cmd/mongo.go b/cmd/mongo.go
index 5948d34..a17eecc 100644
--- a/cmd/mongo.go
+++ b/cmd/mongo.go
@@ -3,6 +3,7 @@ package logmower
 import (
 	"context"
 	"fmt"
+	"time"
 
 	prom "github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
@@ -16,15 +17,15 @@ var (
 		Namespace: PrometheusPrefix,
 		Subsystem: "database",
 		Name:      "heartbeat_time",
-		Help:      "Time in ns for succeeded heartbeat, or 0 on failure",
-		Buckets:   []float64{1},
+		Help:      "Time in seconds for succeeded heartbeat, or 0 on failure",
+		Buckets:   []float64{0.1, 0.2, 0.5, 1, 5, 10, 50},
 	}, []string{"connection_id"})
 
 	promDbCmd = promauto.NewHistogramVec(prom.HistogramOpts{
 		Namespace: PrometheusPrefix,
 		Subsystem: "database",
 		Name:      "operation_latency", // "command_time",
-		Help:      "Time in ns of commands",
+		Help:      "Time in seconds of commands",
 		Buckets:   []float64{0.1, 0.2, 0.5, 1, 5, 10, 50},
 	}, []string{"connection_id", "command_name"})
 
@@ -40,7 +41,7 @@ func mongoMonitoredClientOptions(l *zap.Logger) *mongoOpt.ClientOptions {
 	return mongoOpt.Client().
 		SetServerMonitor(&mongoEvent.ServerMonitor{
 			ServerHeartbeatSucceeded: func(ev *mongoEvent.ServerHeartbeatSucceededEvent) {
-				promDbHeartbeat.WithLabelValues(ev.ConnectionID).Observe(float64(ev.DurationNanos))
+				promDbHeartbeat.WithLabelValues(ev.ConnectionID).Observe(time.Duration(ev.DurationNanos).Seconds())
 			},
 			ServerHeartbeatFailed: func(ev *mongoEvent.ServerHeartbeatFailedEvent) {
 				promDbHeartbeat.WithLabelValues(ev.ConnectionID).Observe(0)
@@ -49,10 +50,10 @@ func mongoMonitoredClientOptions(l *zap.Logger) *mongoOpt.ClientOptions {
 		}).
 		SetMonitor(&mongoEvent.CommandMonitor{
 			Succeeded: func(_ context.Context, ev *mongoEvent.CommandSucceededEvent) {
-				promDbCmd.WithLabelValues(ev.ConnectionID, ev.CommandName).Observe(float64(ev.DurationNanos))
+				promDbCmd.WithLabelValues(ev.ConnectionID, ev.CommandName).Observe(time.Duration(ev.DurationNanos).Seconds())
 			},
 			Failed: func(_ context.Context, ev *mongoEvent.CommandFailedEvent) {
-				promDbCmd.WithLabelValues(ev.ConnectionID, ev.CommandName).Observe(float64(ev.DurationNanos))
+				promDbCmd.WithLabelValues(ev.ConnectionID, ev.CommandName).Observe(time.Duration(ev.DurationNanos).Seconds())
 
 				promDbCmdErr.WithLabelValues(ev.ConnectionID, ev.CommandName).Add(1)
 				l.Error("database command", zap.Error(fmt.Errorf("%s", ev.Failure)), zap.String("connection_id", ev.ConnectionID), zap.String("command_name", ev.CommandName)) // TODO: https://github.com/mongodb/mongo-go-driver/pull/1105