diff --git a/project.clj b/project.clj
index abe057d..ba3a674 100644
--- a/project.clj
+++ b/project.clj
@@ -39,6 +39,7 @@
                  [luminus-immutant "0.2.2"]
                  [overtone/at-at "1.2.0"]
                  [clj.qrgen "0.4.0"]
+                 [digest "1.4.4"]
                  [tentacles "0.5.1"]]
 
   :min-lein-version "2.0.0"
diff --git a/resources/migrations/20160905235051-contracts.down.sql b/resources/migrations/20160905235051-contracts.down.sql
index 1fd9a7b..b4f2c4f 100644
--- a/resources/migrations/20160905235051-contracts.down.sql
+++ b/resources/migrations/20160905235051-contracts.down.sql
@@ -7,3 +7,5 @@ ALTER TABLE public.issues
   DROP COLUMN confirm_hash;
 ALTER TABLE public.issues
   ADD address VARCHAR(256);
+ALTER TABLE public.issues
+  DROP COLUMN comment_id;
diff --git a/resources/migrations/20160905235051-contracts.up.sql b/resources/migrations/20160905235051-contracts.up.sql
index 6be7006..fae02f6 100644
--- a/resources/migrations/20160905235051-contracts.up.sql
+++ b/resources/migrations/20160905235051-contracts.up.sql
@@ -4,6 +4,8 @@ ALTER TABLE public.issues
   ADD contract_address VARCHAR(42) NULL;
 ALTER TABLE public.issues
   ADD confirm_hash VARCHAR(128) NULL;
+ALTER TABLE public.issues
+  ADD comment_id INTEGER NULL;
 -- noinspection SqlResolve
 ALTER TABLE public.issues
   DROP COLUMN address;
diff --git a/resources/sql/queries.sql b/resources/sql/queries.sql
index 9fd68dc..19d3417 100644
--- a/resources/sql/queries.sql
+++ b/resources/sql/queries.sql
@@ -129,6 +129,12 @@ SET contract_address = :contract_address
 FROM t
 RETURNING t.issue_id, t.issue_number, t.title, t.transaction_hash, t.contract_address, t.login, t.repo, t.repo_id;
 
+-- :name update-comment-id :<! :1
+-- :doc updates comment-id for a given issue
+UPDATE issues
+SET comment_id = :comment_id
+WHERE issue_id = :issue_id;
+
 -- :name list-pending-deployments :? :*
 -- :doc retrieves pending transaction ids
 SELECT
@@ -201,8 +207,8 @@ FROM issues i
     ON r.repo_id = i.repo_id
 WHERE r.user_id = :owner_id;
 
--- :name issues-list :? :*
--- :doc lists all issues
+-- :name owner-issues-list :? :*
+-- :doc lists all not yet fixed issues in a given owner's repository
 SELECT
   i.contract_address AS contract_address,
   i.issue_id         AS issue_id,
@@ -215,7 +221,22 @@ FROM issues i
   INNER JOIN repositories r
     ON r.repo_id = i.repo_id
 WHERE r.user_id = :owner_id
-      AND i.commit_id IS NULL;
+      AND i.commit_id IS NULL
+      AND NOT exists(SELECT 1
+                     FROM pull_requests
+                     WHERE issue_number = i.issue_number);
+
+-- :name wallets-list :? :*
+-- :doc lists all contract ids
+SELECT
+  i.contract_address AS contract_address,
+  r.login            AS login,
+  r.repo             AS repo,
+  i.comment_id       AS comment_id,
+  i.issue_number     AS issue_number
+FROM issues i
+  INNER JOIN repositories r ON r.repo_id = i.repo_id
+WHERE contract_address IS NOT NULL;
 
 -- :name get-bounty-address :? :1
 SELECT
diff --git a/src/clj/commiteth/db/bounties.clj b/src/clj/commiteth/db/bounties.clj
index f4204d3..38109dc 100644
--- a/src/clj/commiteth/db/bounties.clj
+++ b/src/clj/commiteth/db/bounties.clj
@@ -12,7 +12,7 @@
 (defn list-not-fixed-issues
   [owner-id]
   (jdbc/with-db-connection [con-db *db*]
-    (db/issues-list con-db {:owner_id owner-id})))
+    (db/owner-issues-list con-db {:owner_id owner-id})))
 
 (defn pending-bounties-list
   []
@@ -28,3 +28,8 @@
   [user repo issue-number]
   (jdbc/with-db-connection [con-db *db*]
     (db/get-bounty-address con-db {:login user :repo repo :issue_number issue-number})))
+
+(defn list-wallets
+  []
+  (jdbc/with-db-connection [con-db *db*]
+    (db/wallets-list con-db)))
diff --git a/src/clj/commiteth/db/issues.clj b/src/clj/commiteth/db/issues.clj
index 597ce14..88b5833 100644
--- a/src/clj/commiteth/db/issues.clj
+++ b/src/clj/commiteth/db/issues.clj
@@ -32,6 +32,13 @@
     (db/update-contract-address con-db {:issue_id         issue-id
                                         :contract_address contract-address})))
 
+(defn update-comment-id
+  "Updates issue with comment id"
+  [issue-id comment-id]
+  (jdbc/with-db-connection [con-db *db*]
+    (db/update-comment-id con-db {:issue_id   issue-id
+                                  :comment_id comment-id})))
+
 (defn list-pending-deployments
   "Retrieves pending transaction ids"
   []
diff --git a/src/clj/commiteth/github/core.clj b/src/clj/commiteth/github/core.clj
index d8f82b5..d9bb5d3 100644
--- a/src/clj/commiteth/github/core.clj
+++ b/src/clj/commiteth/github/core.clj
@@ -6,6 +6,7 @@
             [ring.util.codec :as codec]
             [clj-http.client :as http]
             [commiteth.config :refer [env]]
+            [digest :refer [sha-256]]
             [clojure.tools.logging :as log])
   (:import [java.util UUID]))
 
@@ -93,9 +94,14 @@
   (println "removing webhook")
   (repos/delete-hook user repo hook-id (auth-params token)))
 
+(defn github-comment-hash
+  [user repo issue-number]
+  (digest/sha-256 (str "SALT_Yoh2looghie9jishah7aiphahphoo6udiju" user repo issue-number)))
+
 (defn- get-qr-url
   [user repo issue-number]
-  (str (server-address) (format "/qr/%s/%s/bounty/%s/qr.png" user repo issue-number)))
+  (let [hash (github-comment-hash user repo issue-number)]
+    (str (server-address) (format "/qr/%s/%s/bounty/%s/%s/qr.png" user repo issue-number hash))))
 
 (defn- md-url
   ([text url]
@@ -107,15 +113,25 @@
   [alt src]
   (str "!" (md-url alt src)))
 
+(defn generate-comment
+  [user repo issue-number balance]
+  (let [image-url (md-image "QR Code" (get-qr-url user repo issue-number))
+        balance   (str balance " ETH")
+        site-url  (md-url (server-address) (server-address))]
+    (format "Current balance: %s\n%s\n%s" balance image-url site-url)))
+
 (defn post-comment
   [user repo issue-number balance]
-  (let [balance   (str balance " ETH")
-        image-url (md-image "QR Code" (get-qr-url user repo issue-number))
-        site-url  (md-url (server-address) (server-address))
-        comment   (format "Current balance: %s\n%s\n%s" balance image-url site-url)]
+  (let [comment (generate-comment user repo issue-number balance)]
     (log/info "Comment to" (str user "/" repo) ":" comment)
     (issues/create-comment user repo issue-number comment (self-auth-params))))
 
+(defn update-comment
+  [user repo comment-id issue-number balance]
+  (let [comment (generate-comment user repo issue-number balance)]
+    (log/info (str "Updating " user "/" repo " comment #" comment-id " with contents: " comment))
+    (issues/edit-comment user repo comment-id comment (self-auth-params))))
+
 (defn get-issue
   [user repo issue-number]
   (issues/specific-issue user repo issue-number (self-auth-params)))
diff --git a/src/clj/commiteth/routes/qrcodes.clj b/src/clj/commiteth/routes/qrcodes.clj
index b2c1531..933b143 100644
--- a/src/clj/commiteth/routes/qrcodes.clj
+++ b/src/clj/commiteth/routes/qrcodes.clj
@@ -5,7 +5,8 @@
             [commiteth.layout :as layout]
             [commiteth.util.images :refer :all]
             [clj.qrgen :as qr]
-            [commiteth.eth.core :as eth])
+            [commiteth.eth.core :as eth]
+            [commiteth.github.core :as github])
   (:import [javax.imageio ImageIO]
            [java.io InputStream]))
 
@@ -28,13 +29,15 @@
 
 (defapi qr-routes
   (context "/qr" []
-    (GET "/:user/:repo/bounty/:issue{[0-9]{1,9}}/qr.png" [user repo issue]
-      (let [{address      :contract_address
-             login        :login
-             repo         :repo
-             issue-number :issue_number} (bounties/get-bounty-address user repo (Integer/parseInt issue))
-            balance   (eth/get-balance-eth address 8)
-            issue-url (str login "/" repo "/issues/" issue-number)]
-        (if address
-          (ok (generate-image address balance issue-url 768 256))
-          (bad-request))))))
+    (GET "/:user/:repo/bounty/:issue{[0-9]{1,9}}/:hash/qr.png" [user repo issue hash]
+      (if (= hash (github/github-comment-hash user repo issue))
+        (let [{address      :contract_address
+               login        :login
+               repo         :repo
+               issue-number :issue_number} (bounties/get-bounty-address user repo (Integer/parseInt issue))]
+          (if address
+            (let [balance   (eth/get-balance-eth address 8)
+                  issue-url (str login "/" repo "/issues/" issue-number)]
+              (ok (generate-image address balance issue-url 768 256)))
+            (bad-request)))
+        (bad-request)))))
diff --git a/src/clj/commiteth/scheduler.clj b/src/clj/commiteth/scheduler.clj
index bc4a2b5..d76ca76 100644
--- a/src/clj/commiteth/scheduler.clj
+++ b/src/clj/commiteth/scheduler.clj
@@ -26,8 +26,9 @@
                repo-id      :repo_id
                issue-number :issue_number} issue
               balance            (eth/get-balance-eth contract-address 4)
-              repo-owner-address (:address (users/get-repo-owner repo-id))]
-          (github/post-comment user repo issue-number balance)
+              repo-owner-address (:address (users/get-repo-owner repo-id))
+              {comment-id :id} (github/post-comment user repo issue-number balance)]
+          (issues/update-comment-id issue-id comment-id)
           (wallet/add-owner contract-address (eth/eth-account))
           (wallet/add-owner contract-address repo-owner-address))))))
 
@@ -42,7 +43,19 @@
         (wallet/execute contract-address payout-address value)
         (bounties/update-confirm-hash issue-id)))))
 
+(defn update-balance
+  []
+  (for [{contract-address :contract_address
+         login            :login
+         repo             :repo
+         comment-id       :comment_id
+         issue-number     :issue_number} (bounties/list-wallets)]
+    (when comment-id
+      (let [balance (eth/get-balance-eth contract-address 8)]
+        (github/update-comment login repo comment-id issue-number balance)))))
+
 (mount/defstate scheduler :start
   (do
     (every (* 5 60 1000) update-issue-contract-address pool)
-    (every (* 60 1000) self-sign-bounty pool)))
+    (every (* 60 1000) self-sign-bounty pool)
+    (every (* 5 60 1000) update-balance pool)))