diff --git a/examples/mqttRSSI/mqttRSSI.ino b/examples/mqttRSSI/mqttRSSI.ino
index 766216a..f8bac9e 100644
--- a/examples/mqttRSSI/mqttRSSI.ino
+++ b/examples/mqttRSSI/mqttRSSI.ino
@@ -57,6 +57,7 @@ static const char AUX_mqtt_setting[] PROGMEM = R"raw(
       {
         "name": "mqttserver",
         "type": "ACInput",
+        "value": "",
         "placeholder": "MQTT broker server",
         "label": "Server"
       },
@@ -75,13 +76,26 @@ static const char AUX_mqtt_setting[] PROGMEM = R"raw(
         "type": "ACInput",
         "label": "API Key"
       },
+      {
+        "name": "newline",
+        "type": "ACElement",
+        "value": "<hr>"
+      },
+      {
+        "name": "uniqueid",
+        "type": "ACCheckbox",
+        "value": "unique",
+        "label": "Use APID unique",
+        "checked": false
+      },
       {
         "name": "period",
         "type": "ACRadio",
         "label": "Update period",
         "value": [
           "30 sec.",
-          "60 sec."
+          "60 sec.",
+          "180 sec."
         ],
         "arrange": "vertical",
         "checked": 1
@@ -91,13 +105,6 @@ static const char AUX_mqtt_setting[] PROGMEM = R"raw(
         "type": "ACElement",
         "value": "<hr>"
       },
-      {
-        "name": "uniqueid",
-        "type": "ACCheckbox",
-        "value": "unique",
-        "label": "Use APID unique",
-        "checked": true
-      },
       {
         "name": "hostname",
         "type": "ACInput",
@@ -223,10 +230,10 @@ String loadParams(AutoConnectAux& aux, PageArgument& args) {
   SPIFFS.begin();
   File param = SPIFFS.open(PARAM_FILE, "r");
   if (param) {
-    // if (aux.loadElement(param))
-    //   Serial.println(PARAM_FILE " loaded");
-    // else
-    //   Serial.println(PARAM_FILE " failed to load");
+    if (aux.loadElement(param))
+      Serial.println(PARAM_FILE " loaded");
+    else
+      Serial.println(PARAM_FILE " failed to load");
     param.close();
   }
   else
@@ -341,9 +348,11 @@ void setup() {
     AutoConnectInput&     hostnameElm = setting->getElement<AutoConnectInput>("hostname");
     if (uniqueidElm.checked) {
       config.apid = String("ESP") + "_" + String(ESP.getChipId(), HEX);
+      Serial.println("apid set to " + config.apid);
     }
     if (hostnameElm.value.length()) {
       config.hostName = hostnameElm.value;
+      Serial.println("hostname set to " + config.hostName);
     }
     config.bootUri = AC_ONBOOTURI_HOME;
     config.homeUri = "/";
diff --git a/examples/mqttRSSI_FS/data/mqtt_setting.json b/examples/mqttRSSI_FS/data/mqtt_setting.json
index 2778428..acba2fa 100644
--- a/examples/mqttRSSI_FS/data/mqtt_setting.json
+++ b/examples/mqttRSSI_FS/data/mqtt_setting.json
@@ -18,14 +18,14 @@
     {
       "name": "mqttserver",
       "type": "ACInput",
-      "value": "mqtt.thingspeak.com",
+      "value": "",
       "placeholder": "MQTT broker server",
       "label": "Server"
     },
     {
       "name": "channelid",
       "type": "ACInput",
-      "value": "454951",
+      "value": "",
       "label": "Channel ID"
     },
     {
@@ -37,7 +37,7 @@
     {
       "name": "apikey",
       "type": "ACInput",
-      "value": "HBVQ2XV6VYBI4582",
+      "value": "",
       "label": "API Key"
     },
     {
@@ -62,7 +62,7 @@
       "type": "ACCheckbox",
       "value": "unique",
       "label": "Use APID unique",
-      "checked": true
+      "checked": false
     },
     {
       "name": "hostname",
diff --git a/examples/mqttRSSI_FS/data/param.json b/examples/mqttRSSI_FS/data/param.json
new file mode 100644
index 0000000..a73599b
--- /dev/null
+++ b/examples/mqttRSSI_FS/data/param.json
@@ -0,0 +1,27 @@
+[
+  {
+    "name": "mqttserver",
+    "type": "ACInput",
+    "value": "mqtt.thingspeak.com",
+    "placeholder": "MQTT broker server",
+    "label": "Server"
+  },
+  {
+    "name": "channelid",
+    "type": "ACInput",
+    "value": "454951",
+    "label": "Channel ID"
+  },
+  {
+    "name": "userkey",
+    "type": "ACInput",
+    "value": "NRTFYGJ6TJFGX4RC",
+    "label": "User Key"
+  },
+  {
+    "name": "apikey",
+    "type": "ACInput",
+    "value": "HBVQ2XV6VYBI4582",
+    "label": "API Key"
+  }
+]
diff --git a/examples/mqttRSSI_FS/mqttRSSI_FS.ino b/examples/mqttRSSI_FS/mqttRSSI_FS.ino
index 4a5b1bf..c4c6778 100644
--- a/examples/mqttRSSI_FS/mqttRSSI_FS.ino
+++ b/examples/mqttRSSI_FS/mqttRSSI_FS.ino
@@ -236,9 +236,11 @@ void setup() {
     AutoConnectInput&     hostnameElm = setting->getElement<AutoConnectInput>("hostname");
     if (uniqueidElm.checked) {
       config.apid = String("ESP") + "_" + String(ESP.getChipId(), HEX);
+      Serial.println("apid set to " + config.apid);
     }
     if (hostnameElm.value.length()) {
       config.hostName = hostnameElm.value;
+      Serial.println("hostname set to " + config.hostName);
     }
     config.bootUri = AC_ONBOOTURI_HOME;
     config.homeUri = "/";
diff --git a/src/AutoConnect.cpp b/src/AutoConnect.cpp
index 671f81d..d81840b 100644
--- a/src/AutoConnect.cpp
+++ b/src/AutoConnect.cpp
@@ -662,9 +662,9 @@ bool AutoConnect::_classifyHandle(HTTPMethod method, String uri) {
   // If the current request argument contains AutoConnectElement, it is
   // the form data of the AutoConnectAux page and with this timing save
   // the value of each element.
-  if (_webServer->hasArg(String(AUTOCONNECT_AUXURI_PARAM))) {
+  if (_webServer->hasArg(AUTOCONNECT_AUXURI_PARAM)) {
     String  auxUri = _webServer->arg(AUTOCONNECT_AUXURI_PARAM);
-    auxUri.replace(String("&#47;"), String("/"));
+    auxUri.replace("&#47;", "/");
     AutoConnectAux* aux = _aux.get();
     while (aux) {
       if (aux->_uriStr == auxUri) {
diff --git a/src/AutoConnectAux.cpp b/src/AutoConnectAux.cpp
index f5a2116..6f355c5 100644
--- a/src/AutoConnectAux.cpp
+++ b/src/AutoConnectAux.cpp
@@ -263,7 +263,7 @@ const String AutoConnectAux::_injectMenu(PageArgument& args) {
 const String AutoConnectAux::_indicateUri(PageArgument& args) {
   AC_UNUSED(args);
   String  lastUri = _uriStr;
-  lastUri.replace(String("/"), String("&#47;"));
+  lastUri.replace("/", "&#47;");
   return lastUri;
 }
 
@@ -1118,8 +1118,8 @@ size_t AutoConnectAux::_resultJsonBufferSize() {
     return -1;
   }
   else {
-    AC_DBG("json buffer size:%d\n", _jbSize + _jbByte + 200);
-    return static_cast<size_t>(_jbSize + _jbByte + 200);
+    AC_DBG("json buffer size:%d\n", _jbSize + _jbByte);
+    return static_cast<size_t>(_jbSize + _jbByte);
   }
 }
 
diff --git a/src/AutoConnectDefs.h b/src/AutoConnectDefs.h
index f564942..cb9ee53 100644
--- a/src/AutoConnectDefs.h
+++ b/src/AutoConnectDefs.h
@@ -11,7 +11,7 @@
 #define _AUTOCONNECTDEFS_H_
 
 // Uncomment the following AC_DEBUG to enable debug output.
-#define AC_DEBUG
+//#define AC_DEBUG
 
 // Debug output destination can be defined externally with AC_DEBUG_PORT
 #ifndef AC_DEBUG_PORT
@@ -22,6 +22,7 @@
 #define AC_DBG(...) do {AC_DEBUG_PORT.print("[AC] "); AC_DEBUG_PORT.printf( __VA_ARGS__ );} while (0)
 #else
 #define AC_DBG(...)
+#define AC_DBG_DUMB(...)
 #endif // !AC_DEBUG
 
 // Indicator to specify that AutoConnectAux handles elements with JSON.
diff --git a/src/AutoConnectElement.h b/src/AutoConnectElement.h
index e123a9f..f171aee 100644
--- a/src/AutoConnectElement.h
+++ b/src/AutoConnectElement.h
@@ -22,7 +22,7 @@ using AutoConnectRadio    = AutoConnectRadioJson;
 using AutoConnectSelect   = AutoConnectSelectJson;
 using AutoConnectSubmit   = AutoConnectSubmitJson;
 using AutoConnectText     = AutoConnectTextJson;
-#define AUTOCONNECT_JSON_BUFFER_SIZE  3000
+#define AUTOCONNECT_JSON_BUFFER_SIZE  512
 #else
 using AutoConnectElement  = AutoConnectElementBasis;
 using AutoConnectButton   = AutoConnectButtonBasis;
diff --git a/src/AutoConnectElementBasis.h b/src/AutoConnectElementBasis.h
index 5e3be3b..7e5ba4a 100644
--- a/src/AutoConnectElementBasis.h
+++ b/src/AutoConnectElementBasis.h
@@ -3,7 +3,7 @@
  * @file AutoConnectElementBasis.h
  * @author hieromon@gmail.com
  * @version  0.9.7
- * @date 2018-11-17
+ * @date 2018-12-29
  * @copyright  MIT license.
  */
 
@@ -121,23 +121,15 @@ class AutoConnectInputBasis : virtual public AutoConnectElementBasis {
 class AutoConnectRadioBasis : virtual public AutoConnectElementBasis {
  public:
   explicit AutoConnectRadioBasis(const char* name = "", std::vector<String> const& values = {}, const char* label = "", const ACArrange_t order = AC_Vertical, const uint8_t checked = 0) : AutoConnectElementBasis(name, ""), label(label), order(order), checked(checked), _values(values) {
-    _type = AC_Radio;
-//    _values = values;
-//    for (String v : values) {
-//      add(v);
-//      const std::string sv = v.c_str();
-//      _values.push_back(sv);
-//    }
+   _type = AC_Radio;
   }
   virtual ~AutoConnectRadioBasis() {}
   const String  toHTML(void) const override;
-  void  add(const String& value) { _values.push_back(value); }
-  //void  add(const String& value) {
-  //  std::string sv = value.c_str();
-  //  _values.push_back(sv);
-  //}
-  void  empty(const size_t reserve = 0) { _values.reserve(reserve);  _values.clear(); std::vector<String>().swap(_values); }
+  const String& operator [] (const std::size_t n) const { return at(n); }
+  void  add(const String& value) { _values.push_back(String(value)); }
+  const String& at(const std::size_t n) const { return _values.at(n); }
   void  check(const String& value);
+  void  empty(const size_t reserve = 0);
 
   String      label;    /**< A label for a subsequent radio buttons */
   ACArrange_t order;    /**< layout order */
@@ -145,7 +137,6 @@ class AutoConnectRadioBasis : virtual public AutoConnectElementBasis {
 
  protected:
   std::vector<String> _values; /**< Items in a group */
-//  std::vector<std::string> _values; /**< Items in a group */
 };
 
 /**
@@ -163,8 +154,10 @@ class AutoConnectSelectBasis : virtual public AutoConnectElementBasis {
   }
   virtual ~AutoConnectSelectBasis() {}
   const String  toHTML(void) const override;
-  void  add(const String& option) { _options.push_back(option); }
-  void  empty(const size_t reserve = 0) { _options.reserve(reserve); _options.clear(); std::vector<String>().swap(_options); }
+  const String& operator [] (const std::size_t n) const { return at(n); }
+  void  add(const String& option) { _options.push_back(String(option)); }
+  const String& at(const std::size_t n) const { return _options.at(n); }
+  void  empty(const size_t reserve = 0);
 
   String  label;                /**< A label for a subsequent input box */
 
diff --git a/src/AutoConnectElementBasisImpl.h b/src/AutoConnectElementBasisImpl.h
index a81172b..fa126c4 100644
--- a/src/AutoConnectElementBasisImpl.h
+++ b/src/AutoConnectElementBasisImpl.h
@@ -3,7 +3,7 @@
  * @file AutoConnectElementImpl.h
  * @author hieromon@gmail.com
  * @version  0.9.7
- * @date 2018-11-17
+ * @date 2018-12-29
  * @copyright  MIT license.
  */
 
@@ -64,12 +64,38 @@ const String AutoConnectInputBasis::toHTML(void) const {
   return html;
 }
 
+/**
+* Indicate an entry with the specified value in the value's collection.
+* @param value     The value to indicates in the collection.
+*/
+void AutoConnectRadioBasis::check(const String& value) {
+  for (std::size_t n = 0; n < _values.size(); n++) {
+    if (at(n).equalsIgnoreCase(value)) {
+      checked = n + 1;
+      break;
+    }
+  }
+}
+
+/**
+ * Clear value items of AutoConnetRadio and reallocate new storage.
+ * All hold items are released.
+ * @param reserve  If 'reserve' is greater than 0, this function
+ * allocates new holding storage with the value.
+ */
+void AutoConnectRadioBasis::empty(const size_t reserve) {
+  _values.clear();
+  std::vector<String>().swap(_values);
+  if (reserve)
+    _values.reserve(reserve);
+}
+
 /**
  *  Generate an HTML <input type=radio> element with an <option> element.
  *  @return String  an HTML string.
  */
 const String AutoConnectRadioBasis::toHTML(void) const {
-  String  html = String();
+  String  html = "";
 
   if (label.length()) {
     html = label;
@@ -77,12 +103,12 @@ const String AutoConnectRadioBasis::toHTML(void) const {
       html += String("<br>");
   }
   for (std::size_t n = 0; n < _values.size(); n++) {
-//    String value = _values[n];
-    String value = String(_values[n].c_str());
-    html += String(FPSTR("<input type=\"radio\" name=\"")) + name + String(FPSTR("\" id=\"")) + value + String(FPSTR("\" value=\"")) + value + String("\"");
+    String  value = at(n);
+    String  id = name + "_" + String(n);
+    html += String(FPSTR("<input type=\"radio\" name=\"")) + name + String(FPSTR("\" id=\"")) + id + String(FPSTR("\" value=\"")) + value + String("\"");
     if (n == checked - 1)
       html += String(FPSTR(" checked"));
-    html += String(FPSTR("><label for=\"")) + value + String("\">") + value + String(FPSTR("</label>"));
+    html += String(FPSTR("><label for=\"")) + id + String("\">") + value + String(FPSTR("</label>"));
     if (order == AC_Vertical)
       html += String("<br>");
   }
@@ -90,18 +116,16 @@ const String AutoConnectRadioBasis::toHTML(void) const {
 }
 
 /**
- * Indicate an entry with the specified value in the value's collection.
- * @param value     The value to indicates in the collection.
+ * Clear option items of AutoConnetSelect and reallocate new storage.
+ * All hold items are released.
+ * @param reserve  If 'reserve' is greater than 0, this function
+ * allocates new holding storage with the value.
  */
-void AutoConnectRadioBasis::check(const String& value) {
-  for (std::size_t n = 0; n < _values.size(); n++) {
-//    String& v = _values[n];
-    String v = String(_values[n].c_str());
-    if (v.equalsIgnoreCase(value)) {
-      checked = n + 1;
-      break;
-    }
-  }
+void AutoConnectSelectBasis::empty(const size_t reserve) {
+  _options.clear();
+  std::vector<String>().swap(_options);
+  if (reserve)
+    _options.reserve(reserve);
 }
 
 /**
@@ -113,7 +137,7 @@ void AutoConnectRadioBasis::check(const String& value) {
  *  @return String  an HTML string.
  */
 const String AutoConnectSelectBasis::toHTML(void) const {
-  String  html = String();
+  String  html = "";
 
   if (label.length())
     html = String(FPSTR("<label for=\"")) + name + String("\">") + label + String(FPSTR("</label>"));
diff --git a/src/AutoConnectElementJson.h b/src/AutoConnectElementJson.h
index f4466c9..0f9b9c5 100644
--- a/src/AutoConnectElementJson.h
+++ b/src/AutoConnectElementJson.h
@@ -143,9 +143,6 @@ class AutoConnectRadioJson : public AutoConnectElementJson, public AutoConnectRa
     AutoConnectRadioBasis::label = label;
     AutoConnectRadioBasis::order = order;
     AutoConnectRadioBasis::checked = checked;
-    //for (String v : values) {
-    //  AutoConnectRadioBasis::add(v);
-    //}
   }
   ~AutoConnectRadioJson() {}
   const size_t  getObjectSize(void) const override;
diff --git a/src/AutoConnectElementJsonImpl.h b/src/AutoConnectElementJsonImpl.h
index f1a4ad3..7824441 100644
--- a/src/AutoConnectElementJsonImpl.h
+++ b/src/AutoConnectElementJsonImpl.h
@@ -216,10 +216,6 @@ void AutoConnectRadioJson::serialize(JsonObject& json) {
   json.set(F(AUTOCONNECT_JSON_KEY_TYPE), F(AUTOCONNECT_JSON_TYPE_ACRADIO));
   json.set(F(AUTOCONNECT_JSON_KEY_LABEL), label);
   JsonArray&  values = json.createNestedArray(F(AUTOCONNECT_JSON_KEY_VALUE));
-  //for (std::string& v : _values) {
-  //  String  s = String(v.c_str());
-  //  values.add(s);
-  //}
   for (String v : _values)
     values.add(v);
   switch (order) {