diff --git a/ui/src/Components/SilenceModal/AlertManagerInput/index.js b/ui/src/Components/SilenceModal/AlertManagerInput/index.js
index 08adab106..4d5a5b581 100644
--- a/ui/src/Components/SilenceModal/AlertManagerInput/index.js
+++ b/ui/src/Components/SilenceModal/AlertManagerInput/index.js
@@ -7,16 +7,13 @@ import { observer } from "mobx-react";
 import ReactSelect from "react-select";
 
 import { AlertStore } from "Stores/AlertStore";
-import { SilenceFormStore } from "Stores/SilenceFormStore";
+import {
+  SilenceFormStore,
+  AlertmanagerClustersToOption
+} from "Stores/SilenceFormStore";
 import { MultiSelect, ReactSelectStyles } from "Components/MultiSelect";
 import { ValidationError } from "Components/MultiSelect/ValidationError";
 
-const AlertmanagerClustersToOption = clusterDict =>
-  Object.entries(clusterDict).map(([clusterID, clusterMembers]) => ({
-    label: clusterMembers.join(" | "),
-    value: clusterMembers
-  }));
-
 const AlertManagerInput = observer(
   class AlertManagerInput extends MultiSelect {
     static propTypes = {
@@ -77,6 +74,7 @@ const AlertManagerInput = observer(
           options={AlertmanagerClustersToOption(
             alertStore.data.upstreams.clusters
           )}
+          getOptionValue={JSON.stringify}
           placeholder={
             silenceFormStore.data.wasValidated ? (
               <ValidationError />
diff --git a/ui/src/Components/SilenceModal/SilenceForm.test.js b/ui/src/Components/SilenceModal/SilenceForm.test.js
index 1927b6a50..ca7cbc67c 100644
--- a/ui/src/Components/SilenceModal/SilenceForm.test.js
+++ b/ui/src/Components/SilenceModal/SilenceForm.test.js
@@ -167,9 +167,7 @@ describe("<SilenceForm />", () => {
     matcher.name = "job";
     matcher.values = [{ label: "node_exporter", value: "node_exporter" }];
     silenceFormStore.data.matchers = [matcher];
-    silenceFormStore.data.alertmanagers = [
-      { label: "am1", value: "http://example.com" }
-    ];
+    silenceFormStore.data.alertmanagers = [{ label: "am1", value: ["am1"] }];
     silenceFormStore.data.author = "me@example.com";
     silenceFormStore.data.comment = "fake silence";
     const tree = ShallowSilenceForm();
diff --git a/ui/src/Components/SilenceModal/SilencePreview/index.test.js b/ui/src/Components/SilenceModal/SilencePreview/index.test.js
index 9288082bc..5b4d278c6 100644
--- a/ui/src/Components/SilenceModal/SilencePreview/index.test.js
+++ b/ui/src/Components/SilenceModal/SilencePreview/index.test.js
@@ -75,6 +75,34 @@ describe("<SilencePreview />", () => {
     expect(fetch).toHaveBeenCalled();
   });
 
+  it("fetch uses correct filters with single Alertmanager instance", async () => {
+    fetch.mockResponse(JSON.stringify(MockAPIResponse()));
+    silenceFormStore.data.alertmanagers = [
+      { label: "amName", value: ["amValue"] }
+    ];
+
+    const tree = MountedSilencePreview();
+    await expect(tree.instance().matchedAlerts.fetch).resolves.toBeUndefined();
+    expect(fetch).toHaveBeenCalledWith(
+      "./alerts.json?q=foo%3Dbar&q=%40alertmanager%3D~%5E%28amValue%29%24",
+      { credentials: "include" }
+    );
+  });
+
+  it("fetch uses correct filters with multiple Alertmanager instances", async () => {
+    fetch.mockResponse(JSON.stringify(MockAPIResponse()));
+    silenceFormStore.data.alertmanagers = [
+      { label: "cluster", value: ["am1", "am2"] }
+    ];
+
+    const tree = MountedSilencePreview();
+    await expect(tree.instance().matchedAlerts.fetch).resolves.toBeUndefined();
+    expect(fetch).toHaveBeenCalledWith(
+      "./alerts.json?q=foo%3Dbar&q=%40alertmanager%3D~%5E%28am1%7Cam2%29%24",
+      { credentials: "include" }
+    );
+  });
+
   it("matches snapshot", async () => {
     fetch.mockResponse(JSON.stringify(MockAPIResponse()));
 
diff --git a/ui/src/Stores/SilenceFormStore.js b/ui/src/Stores/SilenceFormStore.js
index 76ca3a5ed..5bb676945 100644
--- a/ui/src/Stores/SilenceFormStore.js
+++ b/ui/src/Stores/SilenceFormStore.js
@@ -19,6 +19,12 @@ const NewEmptyMatcher = () => {
 
 const MatcherValueToObject = value => ({ label: value, value: value });
 
+const AlertmanagerClustersToOption = clusterDict =>
+  Object.entries(clusterDict).map(([clusterID, clusterMembers]) => ({
+    label: clusterMembers.join(" | "),
+    value: clusterMembers
+  }));
+
 const SilenceFormStage = Object.freeze({
   UserInput: "form",
   Preview: "preview",
@@ -155,12 +161,10 @@ class SilenceFormStore {
 
       fillFormFromSilence(alertmanager, silence) {
         this.silenceID = silence.id;
-        this.alertmanagers = [
-          {
-            label: alertmanager.name,
-            value: alertmanager.publicURI
-          }
-        ];
+
+        this.alertmanagers = AlertmanagerClustersToOption({
+          [alertmanager.cluster]: alertmanager.clusterMembers
+        });
 
         const matchers = [];
         for (const m of silence.matchers) {
@@ -214,8 +218,8 @@ class SilenceFormStore {
               m.values.length > 1
                 ? `(${m.values.map(v => v.value).join("|")})`
                 : m.values.length === 1
-                  ? m.values[0].value
-                  : "",
+                ? m.values[0].value
+                : "",
             isRegex: m.isRegex
           })),
           startsAt: this.startsAt
@@ -270,5 +274,6 @@ export {
   SilenceFormStore,
   SilenceFormStage,
   NewEmptyMatcher,
-  MatcherValueToObject
+  MatcherValueToObject,
+  AlertmanagerClustersToOption
 };
diff --git a/ui/src/Stores/SilenceFormStore.test.js b/ui/src/Stores/SilenceFormStore.test.js
index ea1b52e15..44b9195bc 100644
--- a/ui/src/Stores/SilenceFormStore.test.js
+++ b/ui/src/Stores/SilenceFormStore.test.js
@@ -31,7 +31,7 @@ const MockGroup = () => {
 
 const MockAlertmanagerOption = () => ({
   label: "default",
-  value: "http://localhost"
+  value: ["default"]
 });
 
 const MockMatcher = (name, values) => {
@@ -209,7 +209,7 @@ describe("SilenceFormStore.data", () => {
     expect(store.data.alertmanagers).toHaveLength(1);
     expect(store.data.alertmanagers[0]).toMatchObject({
       label: alertmanager.name,
-      value: alertmanager.publicURI
+      value: [alertmanager.name]
     });
 
     expect(store.data.matchers).toHaveLength(2);