diff --git a/Arduino/CanGrow/include/CanGrow_Core.h b/Arduino/CanGrow/include/CanGrow_Core.h
index 75c64c2..648b9e6 100644
--- a/Arduino/CanGrow/include/CanGrow_Core.h
+++ b/Arduino/CanGrow/include/CanGrow_Core.h
@@ -122,6 +122,31 @@ bool Check_GPIOindex_Used(byte gpio) {
       }
     }
   }
+  
+  if(used == false) {
+    for(byte i=0; i < Max_Sensors; i++) {
+      #ifndef DEBUG
+      //Serial.printf("DB [Core:Check_GPIOindex_Used] OutputId: %d , type: %d\n", i, config.system.output.type[i]);
+      #endif    
+      // check if sensor type is gpio
+      if(config.system.sensor.gpio[i] > 0) {
+        #ifndef DEBUG
+        Serial.printf("DB [Core:Check_GPIOindex_Used] SensorId: %d is GPIO (type %d)\n", i, config.system.sensor.gpio[i]);
+        #endif
+        // check if gpio id is already in use
+        if(config.system.sensor.gpio[i] == gpio) {
+          #ifndef DEBUG
+          Serial.printf("DB [Core:Check_GPIOindex_Used] sensor.gpio[%d](%d) == GPIO %d\n", i, config.system.sensor.gpio[i], gpio);
+          #endif
+          used = true;
+          break;        
+        } else {
+          used = false;
+        }
+      }
+    }
+  }
+  
   #ifndef DEBUG
   Serial.printf("DB [Core:Check_GPIOindex_Used] GPIO: %d, used: %d\n", gpio, used);
   #endif
diff --git a/Arduino/CanGrow/include/Webserver/Page_system.h b/Arduino/CanGrow/include/Webserver/Page_system.h
index 2bccc45..e3ebcc5 100644
--- a/Arduino/CanGrow/include/Webserver/Page_system.h
+++ b/Arduino/CanGrow/include/Webserver/Page_system.h
@@ -340,24 +340,22 @@ String Proc_WebPage_system_output(const String& var) {
         output_tr_td += "</td><td>";
         output_tr_td += Output_Type_descr[config.system.output.type[i]];
         
-        if((config.system.output.type[i] == OUTPUT_TYPE_GPIO) || (config.system.output.type[i] == OUTPUT_TYPE_I2C)) {
+        if((config.system.output.type[i] == OUTPUT_TYPE_GPIO) || ( (config.system.output.type[i] == OUTPUT_TYPE_I2C) && (strlen(config.system.output.i2c[i]) > 0) )) {
           output_tr_td += " (";
-        }
         
-        switch(config.system.output.type[i]) {
-          case OUTPUT_TYPE_GPIO:
-            output_tr_td += GPIOindex[config.system.output.gpio[i]].gpio;
-          break;
-          
-          case OUTPUT_TYPE_I2C:
-            output_tr_td += config.system.output.i2c[i];
-          break;
-          
-          default:
-          break;
-        }
+          switch(config.system.output.type[i]) {
+            case OUTPUT_TYPE_GPIO:
+              output_tr_td += GPIOindex[config.system.output.gpio[i]].gpio;
+            break;
+            
+            case OUTPUT_TYPE_I2C:
+              output_tr_td += config.system.output.i2c[i];
+            break;
+            
+            default:
+            break;
+          }
         
-        if((config.system.output.type[i] == OUTPUT_TYPE_GPIO) || (config.system.output.type[i] == OUTPUT_TYPE_I2C)) {
           output_tr_td += ")";
         }
         
@@ -828,7 +826,7 @@ String Proc_WebPage_system_sensor(const String& var) {
         output_tr_td += "</td><td>";
         output_tr_td += SensorIndex[config.system.sensor.type[i]].name;
         
-        if((config.system.sensor.i2c_address[i] != "") || (config.system.sensor.gpio[i] > 0)) {
+        if((strlen(config.system.sensor.i2c_address[i]) > 0) || (config.system.sensor.gpio[i] > 0)) {
           output_tr_td += " (";
           if(config.system.sensor.gpio[i] > 0) {
             output_tr_td += GPIOindex[config.system.sensor.gpio[i]].gpio;