diff --git a/include/ec.h b/include/ec.h
index 9e2f642..1dabaa2 100644
--- a/include/ec.h
+++ b/include/ec.h
@@ -3,8 +3,11 @@
 
 #include <Arduino.h>
 
+float ec_mean=0;
+
 #define EC_PIN_RELAY_PROBE 27
-#define EC_PIN_RELAY_RANGE 25
+#define EC_PIN_RELAY_RANGEMSB 25
+#define EC_PIN_RELAY_RANGELSB 26
 
 
 #define EC_PIN_ADC 4
@@ -14,15 +17,19 @@
 #define EC_FREQUENCY 5000
 
 #define EC_ARRAY_SIZE 128
-uint16_t ec_array_rangeLow[EC_ARRAY_SIZE];
-uint16_t ec_array_rangeHigh[EC_ARRAY_SIZE];
-uint16_t ec_array_pos=EC_ARRAY_SIZE*2;
+uint16_t ec_array_range00[EC_ARRAY_SIZE]; //00=NC,NC = highest value
+uint16_t ec_array_range01[EC_ARRAY_SIZE];
+uint16_t ec_array_range10[EC_ARRAY_SIZE];
+uint16_t ec_array_range11[EC_ARRAY_SIZE]; //11= NO,NO = lowest value
+uint16_t ec_array_pos=EC_ARRAY_SIZE*4;
 #define EC_MEASUREMENT_INTERVAL 10000 //complete filtered measurement every x ms
-  //One filtered measurement takes EC_READ_INTERVAL*EC_ARRAY_SIZE*2
+  //One filtered measurement takes EC_READ_INTERVAL*EC_ARRAY_SIZE*4
 #define EC_READ_INTERVAL 5 //interval of reading adc value inside a measurement
 
 #define EC_RELAY_SWITCH_SETTLETIME 500  //time until voltage of ec circuit has settled
 
+const uint16_t ec_centerADCvalue=1909; //adc value when probe resistance is equal to the range resistor (mean of both)
+
 unsigned long ec_last_change_relay=0; //millis of last relay change
 
 enum ECState{IDLE,MEASURE};
@@ -32,7 +39,7 @@ ECState ecstate=IDLE;
 
 bool ec_measurementReady();
 void ec_startMeasurement();
-void ec_setRange(bool);
+void ec_setRange(uint8_t range);
 void ec_connectProbe(bool);
 void ec_releaseRelay();
 
@@ -44,7 +51,8 @@ void ec_setup() {
   ledcWrite(EC_PWM_CH, 127); //50% duty cycle
 
   pinMode(EC_PIN_RELAY_PROBE,OUTPUT); //LOW=Calibration/idle, HIGH=Probe connected
-  pinMode(EC_PIN_RELAY_RANGE,OUTPUT); //LOW=NC Range Resistor, HIGH=NO Range Resistor
+  pinMode(EC_PIN_RELAY_RANGELSB,OUTPUT); //LOW=NC, HIGH=NO
+  pinMode(EC_PIN_RELAY_RANGEMSB,OUTPUT); //LOW=NC, HIGH=NO
   ec_releaseRelay();
 
 }
@@ -61,17 +69,28 @@ void ec_loop(unsigned long loopmillis) {
         ec_startMeasurement();
         ec_connectProbe(true);
         ecstate=MEASURE;
-        Serial.println("EC Take Measurement");
       }
       break;
 
     case MEASURE:
       if (ec_measurementReady()) {
         ec_releaseRelay();
-        float adc_rangelow=getMean(ec_array_rangeLow,EC_ARRAY_SIZE);
-        float adc_rangehigh=getMean(ec_array_rangeHigh,EC_ARRAY_SIZE);
+        float adc_range00=getMean(ec_array_range00,EC_ARRAY_SIZE); //good for low conductivity/high resistance
+        float adc_range01=getMean(ec_array_range01,EC_ARRAY_SIZE);
+        float adc_range10=getMean(ec_array_range10,EC_ARRAY_SIZE);
+        float adc_range11=getMean(ec_array_range11,EC_ARRAY_SIZE); //good for high conductivity/low resistance
 
-        Serial.print("EC ADC: Low="); Serial.print(adc_rangelow); Serial.print(" High="); Serial.println(adc_rangehigh);
+        
+        ec_mean=0; //TODO select right range of all readings
+
+
+        Serial.println("EC ADC"); 
+        Serial.println(adc_range00);
+        Serial.println(adc_range01);
+        Serial.println(adc_range10);
+        Serial.println(adc_range11);
+        
+        
 
         ecstate=IDLE;
       }
@@ -82,26 +101,33 @@ void ec_loop(unsigned long loopmillis) {
 
 
 
-  if (loopmillis>last_read_ec+EC_READ_INTERVAL && ec_array_pos/2<EC_ARRAY_SIZE) { //take reading into array if measurement running
+  if (loopmillis>last_read_ec+EC_READ_INTERVAL && ec_array_pos/4<EC_ARRAY_SIZE) { //take reading into array if measurement running
     last_read_ec=loopmillis;
 
     //flag_print= ec_array_pos==EC_ARRAY_SIZE;
     //ec_array_pos%=EC_ARRAY_SIZE;
 
-    if (ec_array_pos<EC_ARRAY_SIZE){ //low range
-      ec_setRange(LOW);
-    }else{ //high range
-      ec_setRange(HIGH);
-    }
+    ec_setRange(ec_array_pos/EC_ARRAY_SIZE);
+
 
     if (loopmillis>ec_last_change_relay+EC_RELAY_SWITCH_SETTLETIME) { //values have settled
       uint16_t value=analogRead(EC_PIN_ADC);
-      if (ec_array_pos<EC_ARRAY_SIZE){ //low range
-        ec_array_rangeLow[ec_array_pos%EC_ARRAY_SIZE]=value;
-        
-      }else{ //high range
-        ec_array_rangeHigh[ec_array_pos%EC_ARRAY_SIZE]=value;
-        
+      switch (ec_array_pos/EC_ARRAY_SIZE){ //low range
+        case 0:
+          ec_array_range00[ec_array_pos%EC_ARRAY_SIZE]=value;
+        break;
+
+        case 1:
+          ec_array_range01[ec_array_pos%EC_ARRAY_SIZE]=value;
+        break;
+
+        case 2:
+          ec_array_range10[ec_array_pos%EC_ARRAY_SIZE]=value;
+        break;
+
+        case 3:
+          ec_array_range11[ec_array_pos%EC_ARRAY_SIZE]=value;
+        break;        
       }
 
       
@@ -133,18 +159,23 @@ void ec_startMeasurement() {
 }
 
 bool ec_measurementReady(){
-  if (ec_array_pos>=EC_ARRAY_SIZE*2) { //reached end of both arrays
+  if (ec_array_pos/EC_ARRAY_SIZE>=4) { //reached end of both arrays
     return true;
   }else{
     return false;
   }
 }
 
-void ec_setRange(bool range) {
+void ec_setRange(uint8_t range) {
   //range low means low resistor value -> NO -> relay High
-  bool val=digitalRead(EC_PIN_RELAY_RANGE);
-  if (val!=!range) { //write only if different
-    digitalWrite(EC_PIN_RELAY_RANGE,!range);
+
+  uint8_t crange=digitalRead(EC_PIN_RELAY_RANGELSB)+2*digitalRead(EC_PIN_RELAY_RANGEMSB);
+  
+  if (crange!=range) { //write only if different
+    Serial.print("setRange("); Serial.print(range); Serial.print("), was "); Serial.print(crange);    
+    digitalWrite(EC_PIN_RELAY_RANGELSB,range%2);
+    digitalWrite(EC_PIN_RELAY_RANGEMSB,range/2);
+    Serial.print(". Relay set to "); Serial.print(digitalRead(EC_PIN_RELAY_RANGEMSB)); Serial.print(""); Serial.print(digitalRead(EC_PIN_RELAY_RANGELSB)); Serial.println();
     ec_last_change_relay=millis();
   }
 }
@@ -159,7 +190,8 @@ void ec_connectProbe(bool relay) {
 
 void ec_releaseRelay() {
   digitalWrite(EC_PIN_RELAY_PROBE,LOW);
-  digitalWrite(EC_PIN_RELAY_RANGE,LOW);
+  digitalWrite(EC_PIN_RELAY_RANGEMSB,LOW);
+  digitalWrite(EC_PIN_RELAY_RANGELSB,LOW);
   ec_last_change_relay=millis();
 }