diff --git a/gateway/ceb/ceb.go b/gateway/ceb/ceb.go
index cc09206..4df42c5 100644
--- a/gateway/ceb/ceb.go
+++ b/gateway/ceb/ceb.go
@@ -2,6 +2,7 @@ package ceb
 
 import (
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/hg/airmon/influx"
@@ -25,9 +26,53 @@ type measurement struct {
 	Date          tm.Time `json:"cdate"`
 }
 
+const dataUrl = "https://ceb-uk.kz/map/ajax.php?markers"
 const timeFilename = "ceb-times.json"
+const staleMaxUpdates = 3
+
+type repeat struct {
+	level float64
+	count int
+}
+
+type staleDetector struct {
+	sync.Mutex
+	values map[string]*repeat
+}
+
+func newDetector() *staleDetector {
+	return &staleDetector{
+		values: map[string]*repeat{},
+	}
+}
+
+func (s *staleDetector) isStale(station string, pollutant string, level float64) bool {
+	s.Lock()
+	defer s.Unlock()
+
+	key := station + ":" + pollutant
+
+	rep, ok := s.values[key]
+	if !ok {
+		rep = &repeat{}
+		s.values[key] = rep
+	}
+
+	if rep.level == level {
+		rep.count++
+		if rep.count >= staleMaxUpdates {
+			return true
+		}
+	} else {
+		rep.level = level
+		rep.count = 0
+	}
+
+	return false
+}
 
 type collector struct {
+	stale  *staleDetector
 	sender *influx.MeasurementSender
 	client *net.Client
 	lastAt time.Time
@@ -38,6 +83,7 @@ var log = logger.Get(logger.Ceb)
 func Collect(sender *influx.MeasurementSender) {
 	col := collector{
 		sender: sender,
+		stale:  newDetector(),
 		client: net.NewProxiedClient(),
 		lastAt: loadLastAt(),
 	}
@@ -45,7 +91,7 @@ func Collect(sender *influx.MeasurementSender) {
 		if err := col.run(); err != nil {
 			log.Error("could not get ceb measurements", zap.Error(err))
 		}
-		time.Sleep(15 * time.Minute)
+		time.Sleep(10 * time.Minute)
 	}
 }
 
@@ -82,12 +128,12 @@ func (c *collector) run() error {
 }
 
 func loadLastAt() time.Time {
-	var tm time.Time
-	if err := storage.Load(timeFilename, &tm); err != nil {
+	var t time.Time
+	if err := storage.Load(timeFilename, &t); err != nil {
 		log.Error("could not load last ceb time", zap.Error(err))
-		tm = time.Time{}
+		t = time.Time{}
 	}
-	return tm
+	return t
 }
 
 func saveLastAt(tm time.Time) {
@@ -102,15 +148,27 @@ func (c *collector) saveMeasurement(ms *measurement) {
 		return
 	}
 
+	station := ms.Title
+	pollutant := ms.Pollutant
+	level := ms.ValueMg * 1000
+
+	if c.stale.isStale(station, pollutant, level) {
+		log.Error("value marked as stale and will not be saved",
+			zap.String("station", ms.Title),
+			zap.String("pollutant", ms.Pollutant),
+			zap.Float64("level", ms.ValueMg))
+		return
+	}
+
 	tags := map[string]string{
-		"station":   ms.Title,
+		"station":   station,
 		"address":   ms.Address,
 		"formula":   ms.PollutantFull[:endOfFormula],
-		"pollutant": ms.Pollutant,
+		"pollutant": pollutant,
 	}
 
 	fields := map[string]interface{}{
-		"level_ug": ms.ValueMg * 1000,
+		"level_ug": level,
 		"lat":      ms.Lat,
 		"lon":      ms.Lon,
 	}
@@ -119,6 +177,6 @@ func (c *collector) saveMeasurement(ms *measurement) {
 }
 
 func (c *collector) getResponse() (measurements []measurement, err error) {
-	err = c.client.GetJSON("https://ceb-uk.kz/map/ajax.php?markers", &measurements)
+	err = c.client.GetJSON(dataUrl, &measurements)
 	return
 }
diff --git a/gateway/ceb/ceb_test.go b/gateway/ceb/ceb_test.go
new file mode 100644
index 0000000..3004530
--- /dev/null
+++ b/gateway/ceb/ceb_test.go
@@ -0,0 +1,35 @@
+package ceb
+
+import "testing"
+
+const station = "fake-station"
+const co2 = "co2"
+const so2 = "so2"
+
+func TestStaleDetector(t *testing.T) {
+	d := newDetector()
+
+	for i := 0; i < staleMaxUpdates; i++ {
+		if d.isStale(station, co2, 100) {
+			t.Fatal("value should not be stale")
+		}
+	}
+
+	if d.isStale(station, so2, 50) {
+		t.Fatal("value uses other pollutant and should not be stale")
+	}
+
+	for i := 0; i < staleMaxUpdates*2; i++ {
+		if d.isStale(station, so2, float64(i)) {
+			t.Fatal("value is changing and should not be stale")
+		}
+	}
+
+	if !d.isStale(station, co2, 100) {
+		t.Fatal("value should be stale")
+	}
+
+	if d.isStale(station, co2, 42) {
+		t.Fatal("value has changed and should not be stale")
+	}
+}
diff --git a/gateway/go.mod b/gateway/go.mod
index ed5b6c7..1c8f571 100644
--- a/gateway/go.mod
+++ b/gateway/go.mod
@@ -7,6 +7,6 @@ require (
 	github.com/influxdata/influxdb-client-go/v2 v2.2.0
 	github.com/pkg/errors v0.9.1
 	go.uber.org/multierr v1.6.0 // indirect
-	go.uber.org/zap v1.16.0 // indirect
+	go.uber.org/zap v1.16.0
 	golang.org/x/net v0.0.0-20201110031124-69a78807bb2b
 )
diff --git a/gateway/go.sum b/gateway/go.sum
index a178834..3a2331d 100644
--- a/gateway/go.sum
+++ b/gateway/go.sum
@@ -1,6 +1,8 @@
+github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/cyberdelia/templates v0.0.0-20141128023046-ca7fffd4298c/go.mod h1:GyV+0YP4qX0UQ7r2MoYZ+AvYDp12OF5yg4q8rGnyNh4=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/deepmap/oapi-codegen v1.3.13 h1:9HKGCsdJqE4dnrQ8VerFS0/1ZOJPmAhN+g8xgp8y3K4=
 github.com/deepmap/oapi-codegen v1.3.13/go.mod h1:WAmG5dWY8/PYHt4vKxlt90NsbHMAOCiteYKZMiIRfOo=
@@ -12,14 +14,15 @@ github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeME
 github.com/go-chi/chi v4.0.2+incompatible/go.mod h1:eB3wogJHnLi3x/kFX2A+IbTBlXxmMeXJVKy9tTv1XzQ=
 github.com/golangci/lint-1 v0.0.0-20181222135242-d2cdd8c08219/go.mod h1:/X8TswGSh1pIozq4ZwCfxS0WA5JGXguxk94ar/4c87Y=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
-github.com/influxdata/influxdb-client-go v1.4.0 h1:+KavOkwhLClHFfYcJMHHnTL5CZQhXJzOm5IKHI9BqJk=
 github.com/influxdata/influxdb-client-go/v2 v2.2.0 h1:2R/le0s/MZpHtc+ijuXKe2c4KGN14M85mWtGlmg6vec=
 github.com/influxdata/influxdb-client-go/v2 v2.2.0/go.mod h1:fa/d1lAdUHxuc1jedx30ZfNG573oQTQmUni3N6pcW+0=
 github.com/influxdata/line-protocol v0.0.0-20200327222509-2487e7298839 h1:W9WBk7wlPfJLvMCdtV4zPulc4uCPrlywQOmbFOhgQNU=
 github.com/influxdata/line-protocol v0.0.0-20200327222509-2487e7298839/go.mod h1:xaLFMmpvUxqXtVkUJfg9QmT88cDaCJ3ZKgdZ78oO8Qo=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/labstack/echo/v4 v4.1.11/go.mod h1:i541M3Fj6f76NZtHSj7TXnyM8n2gaodfvfxNnFqi74g=
 github.com/labstack/gommon v0.3.0/go.mod h1:MULnywXg0yavhxWKc+lOruYdAhDwPK9wf0OL7NoOu+k=
@@ -32,11 +35,13 @@ github.com/mattn/go-isatty v0.0.10/go.mod h1:qgIWMr58cqv1PHHyhnkY9lrL7etaEgOFcME
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
 github.com/valyala/fasttemplate v1.0.1/go.mod h1:UQGH1tvbgY+Nz5t2n7tXsz52dQxojPUpymEIMZ47gx8=
@@ -55,6 +60,7 @@ golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20191112222119-e1110fd1c708/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@@ -79,12 +85,15 @@ golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3
 golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191125144606-a911d9008d1f h1:kDxGY2VmgABOe55qheT/TFqUMtcTHnomIPS1iv3G4Ms=
 golang.org/x/tools v0.0.0-20191125144606-a911d9008d1f/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+honnef.co/go/tools v0.0.1-2019.2.3 h1:3JgtbtFHMiCmsznwGVTUWbgGov+pVqnlf1dEJTNAXeM=
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=