diff --git a/htroot/Supporter.java b/htroot/Supporter.java
index 9470e1284..b7310f7f4 100644
--- a/htroot/Supporter.java
+++ b/htroot/Supporter.java
@@ -127,7 +127,7 @@ public class Supporter {
                 row = Supporter.get(urlhash);
                 if (row == null) continue;
 
-                url = row.getPrimaryKeyUTF8();
+                url = row.getPrimaryKeyUTF8().trim();
                 try {
                     if (Switchboard.urlBlacklist.isListed(Blacklist.BLACKLIST_SURFTIPS, new DigestURI(url, urlhash.getBytes()))) continue;
                 } catch(final MalformedURLException e) {continue;}
diff --git a/htroot/Surftips.java b/htroot/Surftips.java
index b019494ab..e9339d00e 100644
--- a/htroot/Surftips.java
+++ b/htroot/Surftips.java
@@ -134,7 +134,7 @@ public class Surftips {
                 row = surftips.get(urlhash);
                 if (row == null) continue;
 
-                url = row.getPrimaryKeyUTF8();
+                url = row.getPrimaryKeyUTF8().trim();
                 try{
                 	if(Switchboard.urlBlacklist.isListed(Blacklist.BLACKLIST_SURFTIPS ,new DigestURI(url)))
                 		continue;
diff --git a/source/net/yacy/kelondro/index/Row.java b/source/net/yacy/kelondro/index/Row.java
index b3032857f..b292fa6ef 100644
--- a/source/net/yacy/kelondro/index/Row.java
+++ b/source/net/yacy/kelondro/index/Row.java
@@ -489,6 +489,13 @@ public final class Row {
             return c;
         }
 
+        /**
+         * get the utf-8 value of the primary key
+         * you will most likely want to call .trim() on that value if the key does not have a fixed length
+         * because the return value may have a fill-up with zero bytes at the end of the string
+         *
+         * @return
+         */
         public final String getPrimaryKeyUTF8() {
             if (this.rowinstance[this.offset] == 0) return null;
             if (Row.this.row.length == 1 && this.offset == 0 && this.rowinstance.length == Row.this.primaryKeyLength) {